ExplorEnz: EC 4.5.1.2

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4.5.1.2

Accepted name:

3-chloro-D-alanine dehydrochlorinase

Reaction:

3-chloro-D-alanine + H₂O = pyruvate + chloride + NH₃ (overall reaction)
(1a) 3-chloro-D-alanine = chloride + 2-aminoprop-2-enoate
(1b) 2-aminoprop-2-enoate = 2-iminopropanoate (spontaneous)
(1c) 2-iminopropanoate + H₂O = pyruvate + NH₃ (spontaneous)

Other name(s):

β-chloro-D-alanine dehydrochlorinase; 3-chloro-D-alanine chloride-lyase (deaminating)

Systematic name:

3-chloro-D-alanine chloride-lyase (deaminating; pyruvate-forming)

Comments:

A pyridoxal-phosphate protein. The enzyme cleaves a carbon-chlorine bond, releasing a chloride and an unstable enamine product that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form pyruvate and ammonia. The latter reaction, which can occur spontaneously, can also be catalysed by EC 3.5.99.10, 2-iminobutanoate/2-iminopropanoate deaminase. The enzyme’s activity can also result in β-replacement reactions, e.g. in the presence of hydrogen sulfide it can convert 3-chloro-D-alanine into D-cysteine and chloride.

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, CAS registry number: 78990-65-5

References:

1.	Nagasawa, T., Ishii, T. and Yamada, H. Physiological comparison of D-cysteine desulfhydrase of Escherichia coli with 3-chloro-D-alanine dehydrochlorinase of Pseudomonas putida CR 1-1. Arch. Microbiol. 149 (1988) 413–416. [PMID: 3132906]
2.	Yamada, H., Nagasawa, T., Ohkishi, H., Kawakami, B. and Tani, Y. Synthesis of D-cysteine from 3-chloro-D-alanine and hydrogen sulfide by 3-chloro-D-alanine hydrogen chloride-lyase (deaminating) of Pseudomonas putida. Biochem. Biophys. Res. Commun. 100 (1981) 1104–1110. [DOI] [PMID: 6791643]

[EC 4.5.1.2 created 1984]