ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Investigations on the β-lysine mutase reaction: Mechanism and steric courseThe steric course and some mechanistic aspects of the coenzyme-B12-dependent β-lysine-mutase reaction, in which (3 S)-β-lysine is converted to (3 S, 5 S)-3, 5-diaminohexanoate, have been investigated by means of tritium labelling. The reaction involves migration of an hydrogen atom from C(5) of the substrate to C(5′) of coenzyme B12 and back-transfer to C(6) of the product. In the presence of [5′-3H]-coenzyme B12 the enzyme catalyzes the exchange of label between the cofactor and one of the diastereotopic H-atoms at C(5) of the substrate. The exchangeable hydrogen atom is identical with the one specifically involved in the migration reaction. Degradation of the tritiated β-lysine obtained in such experiments yielded a sample of tritiated succinic acid which was shown in an enzymic assay involving partial oxidation with succinate dehydrogenase, to possess the (S)-configuration. Thus, the overall substitution at C(5) occurs with inversion of configuration.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19780610824
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