a carboxybiotinyl-[protein] + n Na+in + H+out = CO2 + a biotinyl-[protein] + n Na+out(n = 1–2)
For diagram of the reactions involved in the multienzyme complex malonate decarboxylase, click here
MadB; carboxybiotin protein decarboxylase
The integral membrane protein MadB from the anaerobic bacterium Malonomonas rubra is a component of the multienzyme complex EC 126.96.36.199, biotin-dependent malonate decarboxylase. The free energy of the decarboxylation reaction is used to pump Na+ out of the cell. The enzyme is a member of the Na+-translocating decarboxylase family, other members of which include EC 188.8.131.52 (oxaloacetate decarboxylase) and EC 184.108.40.206 (methylmalonyl-CoA decarboxylase) .
Berg, M., Hilbi, H. and Dimroth, P. Sequence of a gene cluster from Malonomonas rubra encoding components of the malonate decarboxylase Na+ pump and evidence for their function. Eur. J. Biochem.245 (1997) 103–115. [DOI] [PMID: 9128730]
Dimroth, P. and Hilbi, H. Enzymic and genetic basis for bacterial growth on malonate. Mol. Microbiol.25 (1997) 3–10. [DOI] [PMID: 11902724]