Distinct amino termini of two human HCS isoforms influence biotin acceptor substrate recognition.

ABSTRACT: The human holocarboxylase synthetase (HCS) catalyzes transfer of biotin to biotin-dependent carboxylases, and the enzyme is therefore of fundamental importance for many physiological processes, including fatty acid synthesis, gluconeogenesis, and amino acid catabolism. In addition, the enzyme functions in regulating transcription initiation at several genes that code for proteins involved in biotin metabolism. Two major forms of HCS exist in humans, which differ at the amino terminus by 57 amino acids. In this work, the two proteins were expressed in Escherichia coli, purified, and subjected to biochemical characterization. Equilibrium sedimentation indicates that the two proteins are monomers both in their apo-forms and when bound to the enzymatic intermediate biotinyl 5'-AMP. Steady stat

SUBMITTER: Ingaramo M 

PROVIDER: S-EPMC2781485 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature