Mechanism of action of coenzyme B12. Hydrogen transfer in the isomerization of .beta.-methylaspartate to glutamate
| Autor: | M. M. Herbst, J. H. Richards, B. G. Baltimore, R. G. Eagar, H. A. Barker |
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| Rok vydání: | 1972 |
| Předmět: |
Chemical Phenomena
Hydrogen Coenzyme B Stereochemistry Coenzymes chemistry.chemical_element Cleavage (embryo) Photochemistry Biochemistry Mass Spectrometry Cofactor chemistry.chemical_compound Mutase Glutamates Kinetic isotope effect Isomerases Aspartic Acid biology Substrate (chemistry) Deuterium Chemistry Kinetics Vitamin B 12 Models Chemical chemistry biology.protein Isomerization Mathematics |
| Zdroj: | Biochemistry. 11:253-264 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi00752a017 |
| Popis: | Use of a mixture of unlabeled and tetradeuterio-,Bmethylaspartate with coenzyme B_(12) dependent β-methylaspartate-glutamate mutase has shown that the hydrogen that migrates becomes one of three equivalent hydrogens during the isomerization. Kinetic isotope effects suggest that cleavage of the bond in the substrate from carbon to that hydrogen which migrates is an important component of the rate-determining step. The evidence also supports the existence of an intermediate which can partition with similar probabilities to β-methylaspartate or to glutamate. Mechanistic implications of these findings are discussed. |
| Databáze: | OpenAIRE |
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