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ENZYME

ENZYME entry: EC 7.2.4.4

Accepted Name
biotin-dependent malonate decarboxylase
Alternative Name(s)
malonate carboxy-lyase (biotin-dependent)
malonate decarboxylase
Reaction catalysed
H(+) + malonate + Na(+)(in) <=> acetate + CO2 + Na(+)(out)
Comment(s)
  • Two types of malonate decarboxylase are currently known, both of which form multienzyme complexes.
  • The enzyme described here is a membrane-bound biotin-dependent, Na(+)-translocating enzyme.
  • The other type is a biotin-independent cytosolic protein (cf. EC 4.1.1.88).
  • As free malonate is chemically rather inert, it has to be activated prior to decarboxylation.
  • Both enzymes achieve this by exchanging malonate with an acetyl group bound to an acyl-carrier protiein (ACP), to form malonyl-ACP and acetate, with subsequent decarboxylation regenerating the acetyl- bound form of the enzyme.
  • The ACP subunit of both enzymes differs from that found in fatty-acid biosynthesis by having phosphopantethine attached to a serine side- chain as 2-(5-triphosphoribosyl)-3-dephospho-CoA rather than as phosphopantetheine 4'-phosphate.
  • In the anaerobic bacterium Malonomonas rubra, the components of the multienzyme complex/enzymes involved in carrying out the reactions of this enzyme are as follows: MadA (EC 2.3.1.187), MadB (EC 7.2.4.1), MadC/MadD (EC 2.1.3.10) and MadH (EC 6.2.1.35).
  • Two other components that are involved are MadE, the acyl-carrier protein and MadF, the biotin protein.
  • The carboxy group is lost with retention of configuration.
  • Formerly EC 4.1.1.89.
Cross-references
BRENDA7.2.4.4
EC2PDB7.2.4.4
ExplorEnz7.2.4.4
PRIAM enzyme-specific profiles7.2.4.4
KEGG Ligand Database for Enzyme Nomenclature7.2.4.4
IUBMB Enzyme Nomenclature7.2.4.4
IntEnz7.2.4.4
MEDLINEFind literature relating to 7.2.4.4
MetaCyc7.2.4.4
Rhea expert-curated reactions7.2.4.4

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