Cobalt-precorrin 5A hydrolase

Cobalt-precorrin 5A hydrolase, CbiG (gene)) is an enzyme with systematic name cobalt-precorrin 5A acylhydrolase. This enzyme catalyses the following chemical reaction


 * cobalt-precorrin-5A + H2O $$\rightleftharpoons$$ cobalt-precorrin-5B + acetaldehyde + 2 H+

This enzyme hydrolyses the ring A acetate delta-lactone of cobalt-precorrin-5A and releases a two-carbon fragment from the macrocyclic corrin ring as acetaldehyde. This is part of the biosynthetic pathway to cobalamin (vitamin B12) in anaerobic bacteria such as Salmonella typhimurium and Bacillus megaterium.