ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Journal of the American Society for Mass Spectrometry, May 1, 1994
We are currently developing strategies to synthesize bisubstrate analogs as potential inhibitors ... more We are currently developing strategies to synthesize bisubstrate analogs as potential inhibitors of serine and tyrosine protein kinases: several such analogs have been synthesized. The initial target proteins were the cAMP dependent protein kinase (cAPK) and the Ca +2jcalmodulin dependent protein kinase (CaM kinase Il). These bisubstrate analogs were based on either known peptide substrates such as kemptide, a seven amino acid peptide substrate of cAPK, or on inhibitory peptides such as a seventeen amino acid peptide encompassing the autoinhibitory domain of CaM kinase II. Peptides containing a single phosphoserine group were first synthesized and then adenosine 5'-monophosphate (AMP), adenosine 5'-diphosphate (ADP), or adenosine 5 ' -triphosphate (ATP) was coupled through the serine phosphate with prior activation by l,1-earbonyldiimidazole using either a solution or solid phase reaction scheme. In this current study, we report the characterization of the bisubstrate analogs by liquid secondary ionization mass spectrometry (LSIMS), matrixassisted laser desorption mass spectrometry (MALDI), and tandem mass spectrometry (MS/MS). In the positive-ion mode, the LSIMS spectra of the bisubstrate analogs yielded a series of molecular ions containing mono-, di-, and trivalent cation adducts. Cation adducts were absent in the negative-ion mode where the dominant species were deprotonated molecular ions, [M -H] -, making this latter technique more useful for confirming product identity and assessing purity. Analysis of these compounds by MALDI in both the positive-and negative-ion modes yielded molecular ions which also contained metal ion adducts, although they were limited primarily to Fe+ 2 adducts. Unlike LSIMS, the MALDI spectra showed no evidence for the elimination of the phosphoadenosine or other structural moieties. When these compounds were subjected to high energy collision-induced dissociation (CID), the dominant fragmentation pathways under positive-ion MS/MS conditions resulted from cleavage of the phosphate linkages to the adenosine moiety with charge retention on the peptide, although a major peak for 5 ' -d eoxyad enosine was also seen at m rz 250. Charge retention in the negative-ion mode was most pronounced for ion fragments containing the highly acidic phosphate moieties and yielded phosphoadenosine related ions, for example, (AMP-H)-, (AMP-H-H 20)-, (ADP-H)-, etc., as well as ions originating from the phosphate linker such as POi, H 2P04 , HP 206 -, H 3P20i, and H 2P309 . The largest phosphoadenosine ion in the negative-ion cm spectra for each bisubstrate analog, for example, m /z 426 (ADP-H)-, m rz 506 (ATP-H)-, or m/z 586 (AP 4-H)-, indicated that the desired covalent modification had been formed between the phosphoserine and AP n moieties. (JAm Soc Mass Spectrom 1994, 5, 443-451
The enzymes of the mandelate metabolic pathway permit Pseudomonas putida ATCC 12633 to utilize ei... more The enzymes of the mandelate metabolic pathway permit Pseudomonas putida ATCC 12633 to utilize either or both enantiomers of mandelate as the sole carbon source. The genes encoding the mandelate pathway were found to lie on a single 10.5-kb restriction fragment. Part of that fragment was shown to contain the genes coding for mandelate racemase, mandelate dehydrogenase, and benzoylformate decarboxylase arranged in an operon. Here we report the sequencing of the remainder of the restriction fragment, which revealed three further open reading frames, denoted mdlX, mdlY, and mdlD. All were transcribed in the opposite direction from the genes of the mdlABC operon. Sequence alignments suggested that the open reading frames encoded a regulatory protein (mdlX), a member of the amidase signature family (mdlY), and an NAD(P) ؉ -dependent dehydrogenase (mdlD). The mdlY and mdlD genes were isolated and expressed in Escherichia coli, and the purified gene products were characterized as a mandelamide hydrolase and an NAD(P) ؉ -dependent benzaldehyde dehydrogenase, respectively.
Abstract A new, direct kinetic assay for mandelate racemase has been developed. The assay depends... more Abstract A new, direct kinetic assay for mandelate racemase has been developed. The assay depends upon changes with time in circular dichroic ellipticities of mandelate solutions at 262 nm. The technique should allow more precise kinetic measurements of the mandelate racemase reaction than have heretofore been possible. Also, the approach to equilibrium can be measured from either ( R )- or ( S )-mandelate with equal facility. The technique, should, moreover, be extendible to other enzyme-catalyzed reactions involving changes with time in circular dichroic ellipticities.
Biochemical and Biophysical Research Communications, Mar 1, 1990
Human immunodeficiency virus-1 reverse transcriptase-p66 is surprisingly unstable at 4 degrees C ... more Human immunodeficiency virus-1 reverse transcriptase-p66 is surprisingly unstable at 4 degrees C in a typical reverse transcriptase buffer that provides complete stability when enzyme is frozen at -70 degrees C. Incorporation of (rA)n(dT)12-18 template-primer in the buffer vastly improved solution stability of dilute enzyme. Incorporation of 1.0 M ammonium phosphate in the buffer promoted an unexpected and reproducible approximately 260% activation of enzyme. In addition, even enzyme that had been inactivated to 13% of its initial activity could be reactivated to the same approximately 260% higher activity level indicating a reversible interconversion of two forms of the enzyme. The effects of chaotropic and antichaotropic salts coupled with a prior observation of p66 monomer-dimer equilibrium provide suggestive evidence that these two forms of enzyme are monomeric and dimeric p66.
The entire family of A T P analogues that are either mono-or disubstituted with imido and methyle... more The entire family of A T P analogues that are either mono-or disubstituted with imido and methylene bridges in the polyphosphate chain of ATP have been investigated as substrates and inhibitors of S-adenosylmethionine synthetase (ATP:L-methionine S-adenosyltransferase). The disubstituted analogues adenosine S-(a,P:P,y-diimidotriphosphate) (AMPNPNP) and adenosine S-(a,P:a,/3'-diimidotriphosphate) [AMP(NP),] have been synthesized for the first time, and a new route to adenosine 5'-(a,/3$,y-dimethylenetriphosphate) (AMPCPCP) has been developed. S-Adenosylmethionine synthetase catalyzes a two-step reaction: the intact polyphosphate chain is displaced from ATP, yielding AdoMet and tripolyphosphate, followed normally, but not obligatorily, by the hydrolysis of the tripolyphosphate to pyrophosphate and orthophosphate. Uniformly, the imido mono-or disubstituted derivatives are both better substrates and better inhibitors than their methylene counterparts. AMPNPNP reacts rapidly to give a single equivalent 'This work was supported by U S . Public Health Service Grants GM-39552 and AR-17323 (to G.L.K.), GM-31186 (to G.D.M.), and CA-06927 and RR-05539 (to the Fox Chase Cancer Center) and also an appropriation from the Commonwealth of Pennsylvania.
Creatine kinase (CK; EC 2.7.3.2) catalyzes the reversible conversion of creatine and MgATP to pho... more Creatine kinase (CK; EC 2.7.3.2) catalyzes the reversible conversion of creatine and MgATP to phosphocreatine and MgADP. In the absence of an X-ray crystal structure, we have used the sequence homology of creatine kinases and other guanidino kinases from a variety of sources to identify the conserved histidine residues in rabbit muscle CK, as well as to try to pinpoint a reactive histidine that has been implicated in the active site. This residue has been proposed to act as a general acid/base catalyst assisting in the phosphoryl transfer mechanism ) Biochemistry 20, 1204-1210]. There are 17 histidine residues in rabbit muscle CK, and of these, only five have been conserved in all guanidino kinase sequences published to date [Mu ¨hlebach et al. (1994) Mol. Cell. Biochem. 133, 245-62]. In rabbit muscle CK, these residues are H96, H105, H190, H233, and H295. We have carried out sitespecific mutagenesis of these five histidine residues, replacing each with an asparagine. Each of these mutants exhibited enzymatic activity but to varying degrees. The H105N, H190N, and H233N mutants displayed specific activities similar to that of the wild-type enzyme. H96N has high activity, but appears to be quite unstable, losing catalytic activity upon cell lysis by sonication and/or chromatographic steps involved in purification. H295N shows a significantly reduced catalytic activity relative to the native enzyme, due to marked decreases in k cat and the affinities for both substrates. Each of the five mutants is inactivated by diethyl pyrocarbonate (DEP), and inactivation is reversible upon incubation with hydroxylamine. However, only H295N shows a dramatically reduced rate of inactivation relative to native CK, consistent with H295 being the residue modified by DEP in the native enzyme. These intriguing results indicate that four of the conserved histidines (H96, H105, H295, and H233) are not essential for activity, and while H295 may be at the active site of CK, it is unlikely to play the role of a general acid/base catalyst.
Advances in Enzymology and Related Areas of Molecular Biology, Nov 22, 2006
Page 1. CREATINE KINASE: S T RU C TU R E-ACT1 VI T YR ELATION SH IP S By GEORGE L. KENYON, Depart... more Page 1. CREATINE KINASE: S T RU C TU R E-ACT1 VI T YR ELATION SH IP S By GEORGE L. KENYON, Department ofPhamaceutica1 Chemistry, School of Pharmacy, University of California, San Francisco, Califor-nia 94143 ...
the protection experiments is approximately 5 mM. The results indicate that a-phenylglycidate bin... more the protection experiments is approximately 5 mM. The results indicate that a-phenylglycidate binds at the active site of the enzyme and that it is therefore an affinity label. When the enzyme was irreversibly inhibited with either @-[l"C]-or 0-
crystallographically a productive substrate-enzyme complex 9. Kenyon, G. L., and Hegeman, G. D. (... more crystallographically a productive substrate-enzyme complex 9. Kenyon, G. L., and Hegeman, G. D. (1970) Biochemistry 9,4036in assessing the nature of structural rearrangements associated with catalysis. (18) ' The structure Of such a be Of great 10
Burger's Medicinal Chemistry and Drug Discovery, Jan 15, 2003
Skip to Main Content. Wiley Online Library will be disrupted 3 Sep from 10-12 BST for monthly mai... more Skip to Main Content. Wiley Online Library will be disrupted 3 Sep from 10-12 BST for monthly maintenance. ...
The pET17 expression vector was used to express creatine kinase from the electric organ of Torped... more The pET17 expression vector was used to express creatine kinase from the electric organ of Torpedo californica as inclusion bodies in Escherichia coli BL21(DE3) cells. The insoluble aggregate was dissolved in 8 M urea and, following extraction with Triton X-100, the enzyme was refolded by dialysis against Tris buffer (pH 8.0) containing 0.2 M NaCl. After two buffer changes, chromatography on Blue Sepharose was used as a final step in the purification procedure. Approximately 54 mg active protein was recovered from a 1 L culture and the refolded enzyme had a specific activity of 75 U/mg. The molecular mass of the purified protein was consistent with that predicted from the amino acid sequence and the CD spectrum of the refolded enzyme was essentially identical to that of creatine kinase from human muscle (HMCK). The K m values of ATP and ADP were also similar to those of HMCK, while the K m values for both phosphocreatine and creatine were approximately 5-10-fold higher. The purification described here is in marked contrast with earlier attempts at purification of this isozyme where, in a process yielding less than 1 mg/L culture, enzyme with a specific activity of ca. 5 U/mg was obtained.
In aqueous base, each of the two stereoisomeric 1 ,Z-dibromo-1-phenylpropylphosphonic acids decom... more In aqueous base, each of the two stereoisomeric 1 ,Z-dibromo-1-phenylpropylphosphonic acids decomposes stereospecifically to yield inorganic phosphate and bromide ions, and a single isomer of l-bromo-l-propenylbenzene. Evidence is presented to show that the erythro dibromide yields the cis-bromopropenylbenzene, and the threo dibromide yields the trans-bromopropenylbenzene. The fragmentation proceeds by a trans elimination of halide ion and a phosphorus moiety which behaves like the hypothetical monomeric metaphosphate ion.
Die verschiedenen Methoden zur Synthese von 1-Methyl-2-amino-2-imidazolin-4-on (VII) aus Glycin (... more Die verschiedenen Methoden zur Synthese von 1-Methyl-2-amino-2-imidazolin-4-on (VII) aus Glycin (I) werden hinsichtlich einer Ausbeute-Optimierung untersucht und f ür das angegebene, mit 91% verlaufende Verfahren auf die Überf ührung von markiertem Glycin in 4-13C-1-Methyl-2-amino-2-imidazolin-4-on angewandt.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Journal of the American Society for Mass Spectrometry, May 1, 1994
We are currently developing strategies to synthesize bisubstrate analogs as potential inhibitors ... more We are currently developing strategies to synthesize bisubstrate analogs as potential inhibitors of serine and tyrosine protein kinases: several such analogs have been synthesized. The initial target proteins were the cAMP dependent protein kinase (cAPK) and the Ca +2jcalmodulin dependent protein kinase (CaM kinase Il). These bisubstrate analogs were based on either known peptide substrates such as kemptide, a seven amino acid peptide substrate of cAPK, or on inhibitory peptides such as a seventeen amino acid peptide encompassing the autoinhibitory domain of CaM kinase II. Peptides containing a single phosphoserine group were first synthesized and then adenosine 5'-monophosphate (AMP), adenosine 5'-diphosphate (ADP), or adenosine 5 ' -triphosphate (ATP) was coupled through the serine phosphate with prior activation by l,1-earbonyldiimidazole using either a solution or solid phase reaction scheme. In this current study, we report the characterization of the bisubstrate analogs by liquid secondary ionization mass spectrometry (LSIMS), matrixassisted laser desorption mass spectrometry (MALDI), and tandem mass spectrometry (MS/MS). In the positive-ion mode, the LSIMS spectra of the bisubstrate analogs yielded a series of molecular ions containing mono-, di-, and trivalent cation adducts. Cation adducts were absent in the negative-ion mode where the dominant species were deprotonated molecular ions, [M -H] -, making this latter technique more useful for confirming product identity and assessing purity. Analysis of these compounds by MALDI in both the positive-and negative-ion modes yielded molecular ions which also contained metal ion adducts, although they were limited primarily to Fe+ 2 adducts. Unlike LSIMS, the MALDI spectra showed no evidence for the elimination of the phosphoadenosine or other structural moieties. When these compounds were subjected to high energy collision-induced dissociation (CID), the dominant fragmentation pathways under positive-ion MS/MS conditions resulted from cleavage of the phosphate linkages to the adenosine moiety with charge retention on the peptide, although a major peak for 5 ' -d eoxyad enosine was also seen at m rz 250. Charge retention in the negative-ion mode was most pronounced for ion fragments containing the highly acidic phosphate moieties and yielded phosphoadenosine related ions, for example, (AMP-H)-, (AMP-H-H 20)-, (ADP-H)-, etc., as well as ions originating from the phosphate linker such as POi, H 2P04 , HP 206 -, H 3P20i, and H 2P309 . The largest phosphoadenosine ion in the negative-ion cm spectra for each bisubstrate analog, for example, m /z 426 (ADP-H)-, m rz 506 (ATP-H)-, or m/z 586 (AP 4-H)-, indicated that the desired covalent modification had been formed between the phosphoserine and AP n moieties. (JAm Soc Mass Spectrom 1994, 5, 443-451
The enzymes of the mandelate metabolic pathway permit Pseudomonas putida ATCC 12633 to utilize ei... more The enzymes of the mandelate metabolic pathway permit Pseudomonas putida ATCC 12633 to utilize either or both enantiomers of mandelate as the sole carbon source. The genes encoding the mandelate pathway were found to lie on a single 10.5-kb restriction fragment. Part of that fragment was shown to contain the genes coding for mandelate racemase, mandelate dehydrogenase, and benzoylformate decarboxylase arranged in an operon. Here we report the sequencing of the remainder of the restriction fragment, which revealed three further open reading frames, denoted mdlX, mdlY, and mdlD. All were transcribed in the opposite direction from the genes of the mdlABC operon. Sequence alignments suggested that the open reading frames encoded a regulatory protein (mdlX), a member of the amidase signature family (mdlY), and an NAD(P) ؉ -dependent dehydrogenase (mdlD). The mdlY and mdlD genes were isolated and expressed in Escherichia coli, and the purified gene products were characterized as a mandelamide hydrolase and an NAD(P) ؉ -dependent benzaldehyde dehydrogenase, respectively.
Abstract A new, direct kinetic assay for mandelate racemase has been developed. The assay depends... more Abstract A new, direct kinetic assay for mandelate racemase has been developed. The assay depends upon changes with time in circular dichroic ellipticities of mandelate solutions at 262 nm. The technique should allow more precise kinetic measurements of the mandelate racemase reaction than have heretofore been possible. Also, the approach to equilibrium can be measured from either ( R )- or ( S )-mandelate with equal facility. The technique, should, moreover, be extendible to other enzyme-catalyzed reactions involving changes with time in circular dichroic ellipticities.
Biochemical and Biophysical Research Communications, Mar 1, 1990
Human immunodeficiency virus-1 reverse transcriptase-p66 is surprisingly unstable at 4 degrees C ... more Human immunodeficiency virus-1 reverse transcriptase-p66 is surprisingly unstable at 4 degrees C in a typical reverse transcriptase buffer that provides complete stability when enzyme is frozen at -70 degrees C. Incorporation of (rA)n(dT)12-18 template-primer in the buffer vastly improved solution stability of dilute enzyme. Incorporation of 1.0 M ammonium phosphate in the buffer promoted an unexpected and reproducible approximately 260% activation of enzyme. In addition, even enzyme that had been inactivated to 13% of its initial activity could be reactivated to the same approximately 260% higher activity level indicating a reversible interconversion of two forms of the enzyme. The effects of chaotropic and antichaotropic salts coupled with a prior observation of p66 monomer-dimer equilibrium provide suggestive evidence that these two forms of enzyme are monomeric and dimeric p66.
The entire family of A T P analogues that are either mono-or disubstituted with imido and methyle... more The entire family of A T P analogues that are either mono-or disubstituted with imido and methylene bridges in the polyphosphate chain of ATP have been investigated as substrates and inhibitors of S-adenosylmethionine synthetase (ATP:L-methionine S-adenosyltransferase). The disubstituted analogues adenosine S-(a,P:P,y-diimidotriphosphate) (AMPNPNP) and adenosine S-(a,P:a,/3'-diimidotriphosphate) [AMP(NP),] have been synthesized for the first time, and a new route to adenosine 5'-(a,/3$,y-dimethylenetriphosphate) (AMPCPCP) has been developed. S-Adenosylmethionine synthetase catalyzes a two-step reaction: the intact polyphosphate chain is displaced from ATP, yielding AdoMet and tripolyphosphate, followed normally, but not obligatorily, by the hydrolysis of the tripolyphosphate to pyrophosphate and orthophosphate. Uniformly, the imido mono-or disubstituted derivatives are both better substrates and better inhibitors than their methylene counterparts. AMPNPNP reacts rapidly to give a single equivalent 'This work was supported by U S . Public Health Service Grants GM-39552 and AR-17323 (to G.L.K.), GM-31186 (to G.D.M.), and CA-06927 and RR-05539 (to the Fox Chase Cancer Center) and also an appropriation from the Commonwealth of Pennsylvania.
Creatine kinase (CK; EC 2.7.3.2) catalyzes the reversible conversion of creatine and MgATP to pho... more Creatine kinase (CK; EC 2.7.3.2) catalyzes the reversible conversion of creatine and MgATP to phosphocreatine and MgADP. In the absence of an X-ray crystal structure, we have used the sequence homology of creatine kinases and other guanidino kinases from a variety of sources to identify the conserved histidine residues in rabbit muscle CK, as well as to try to pinpoint a reactive histidine that has been implicated in the active site. This residue has been proposed to act as a general acid/base catalyst assisting in the phosphoryl transfer mechanism ) Biochemistry 20, 1204-1210]. There are 17 histidine residues in rabbit muscle CK, and of these, only five have been conserved in all guanidino kinase sequences published to date [Mu ¨hlebach et al. (1994) Mol. Cell. Biochem. 133, 245-62]. In rabbit muscle CK, these residues are H96, H105, H190, H233, and H295. We have carried out sitespecific mutagenesis of these five histidine residues, replacing each with an asparagine. Each of these mutants exhibited enzymatic activity but to varying degrees. The H105N, H190N, and H233N mutants displayed specific activities similar to that of the wild-type enzyme. H96N has high activity, but appears to be quite unstable, losing catalytic activity upon cell lysis by sonication and/or chromatographic steps involved in purification. H295N shows a significantly reduced catalytic activity relative to the native enzyme, due to marked decreases in k cat and the affinities for both substrates. Each of the five mutants is inactivated by diethyl pyrocarbonate (DEP), and inactivation is reversible upon incubation with hydroxylamine. However, only H295N shows a dramatically reduced rate of inactivation relative to native CK, consistent with H295 being the residue modified by DEP in the native enzyme. These intriguing results indicate that four of the conserved histidines (H96, H105, H295, and H233) are not essential for activity, and while H295 may be at the active site of CK, it is unlikely to play the role of a general acid/base catalyst.
Advances in Enzymology and Related Areas of Molecular Biology, Nov 22, 2006
Page 1. CREATINE KINASE: S T RU C TU R E-ACT1 VI T YR ELATION SH IP S By GEORGE L. KENYON, Depart... more Page 1. CREATINE KINASE: S T RU C TU R E-ACT1 VI T YR ELATION SH IP S By GEORGE L. KENYON, Department ofPhamaceutica1 Chemistry, School of Pharmacy, University of California, San Francisco, Califor-nia 94143 ...
the protection experiments is approximately 5 mM. The results indicate that a-phenylglycidate bin... more the protection experiments is approximately 5 mM. The results indicate that a-phenylglycidate binds at the active site of the enzyme and that it is therefore an affinity label. When the enzyme was irreversibly inhibited with either @-[l"C]-or 0-
crystallographically a productive substrate-enzyme complex 9. Kenyon, G. L., and Hegeman, G. D. (... more crystallographically a productive substrate-enzyme complex 9. Kenyon, G. L., and Hegeman, G. D. (1970) Biochemistry 9,4036in assessing the nature of structural rearrangements associated with catalysis. (18) ' The structure Of such a be Of great 10
Burger's Medicinal Chemistry and Drug Discovery, Jan 15, 2003
Skip to Main Content. Wiley Online Library will be disrupted 3 Sep from 10-12 BST for monthly mai... more Skip to Main Content. Wiley Online Library will be disrupted 3 Sep from 10-12 BST for monthly maintenance. ...
The pET17 expression vector was used to express creatine kinase from the electric organ of Torped... more The pET17 expression vector was used to express creatine kinase from the electric organ of Torpedo californica as inclusion bodies in Escherichia coli BL21(DE3) cells. The insoluble aggregate was dissolved in 8 M urea and, following extraction with Triton X-100, the enzyme was refolded by dialysis against Tris buffer (pH 8.0) containing 0.2 M NaCl. After two buffer changes, chromatography on Blue Sepharose was used as a final step in the purification procedure. Approximately 54 mg active protein was recovered from a 1 L culture and the refolded enzyme had a specific activity of 75 U/mg. The molecular mass of the purified protein was consistent with that predicted from the amino acid sequence and the CD spectrum of the refolded enzyme was essentially identical to that of creatine kinase from human muscle (HMCK). The K m values of ATP and ADP were also similar to those of HMCK, while the K m values for both phosphocreatine and creatine were approximately 5-10-fold higher. The purification described here is in marked contrast with earlier attempts at purification of this isozyme where, in a process yielding less than 1 mg/L culture, enzyme with a specific activity of ca. 5 U/mg was obtained.
In aqueous base, each of the two stereoisomeric 1 ,Z-dibromo-1-phenylpropylphosphonic acids decom... more In aqueous base, each of the two stereoisomeric 1 ,Z-dibromo-1-phenylpropylphosphonic acids decomposes stereospecifically to yield inorganic phosphate and bromide ions, and a single isomer of l-bromo-l-propenylbenzene. Evidence is presented to show that the erythro dibromide yields the cis-bromopropenylbenzene, and the threo dibromide yields the trans-bromopropenylbenzene. The fragmentation proceeds by a trans elimination of halide ion and a phosphorus moiety which behaves like the hypothetical monomeric metaphosphate ion.
Die verschiedenen Methoden zur Synthese von 1-Methyl-2-amino-2-imidazolin-4-on (VII) aus Glycin (... more Die verschiedenen Methoden zur Synthese von 1-Methyl-2-amino-2-imidazolin-4-on (VII) aus Glycin (I) werden hinsichtlich einer Ausbeute-Optimierung untersucht und f ür das angegebene, mit 91% verlaufende Verfahren auf die Überf ührung von markiertem Glycin in 4-13C-1-Methyl-2-amino-2-imidazolin-4-on angewandt.
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