CATH Classification

Domain Context

CATH Clusters

Superfamily Type I PLP-dependent aspartate aminotransferase-like (Major domain)
Functional Family Cystathionine beta-lyase

Enzyme Information

4.4.1.28
L-cysteine desulfidase.
based on mapping to UniProt P06721
L-cysteine + H(2)O = sulfide + NH(3) + pyruvate.
-!- The enzyme from the archaeon Methanocaldococcus jannaschii contains a [4Fe-4S] cluster and is specific for L-cysteine (cf. EC 4.4.1.1). -!- It cleaves a carbon-sulfur bond releasing sulfide and the unstable enamine product 2-aminoprop-2-enoate that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form pyruvate and ammonia. -!- The same reaction can also be catalyzed by some pyridoxal-phosphate proteins (cf. EC 4.4.1.1).
4.4.1.13
Cysteine-S-conjugate beta-lyase.
based on mapping to UniProt P06721
An L-cysteine-S-conjugate + H(2)O = RSH + NH(3) + pyruvate.
-!- A pyridoxal 5'-phosphate protein. -!- The enzyme is promiscuous regarding the moiety conjugated to L-cysteine, and can accept both aliphatic and aromatic substitutions. -!- The enzyme cleaves a carbon-sulfur bond, releasing a thiol and an unstable enamine product that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form pyruvate and ammonia. -!- While bacteria and plants have dedicated enzymes, all of the animal enzymes discovered thus far are bifunctional, most of which also act as aminotransferases. -!- Formerly EC 4.4.1.6 and EC 4.4.1.8.

UniProtKB Entries (1)

P06721
METC_ECOLI
Escherichia coli K-12
Cystathionine beta-lyase MetC

PDB Structure

PDB 4ITX
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Structure and activity of P113S mutant of E. coli Cystathionine beta-lyase (MetC)
Soo, V.W.C., Yosaatmadja, Y., Squire, C.J., Patrick, W.M.
To be Published