The odd- and branched-chain fatty acids (OBCFA) accumulated in ruminant products are a class of beneficial for human health. Since biotin leucine involved OBCFA synthesis, this study aimed to evaluate their effect on synthesis vitro. There were four treatments: the control group that only provided basal diet, or diet supplemented with (4 mg/kg dry matter, DM), g/kg combination DM) DM). results ...

In an earlier s tudy 1, 2 of leucine metabolism in crude heart extracts, da ta were obtained indicating that fl-methylcrotonyl CoA is acted upon by enoyl hydrase (crotonase) and tha t the resulting fl-hydroxyisovaleryl CoA is carboxylated enzymically in the presence of ATP to yield fl-hydroxy-fl-methylglutaryl CoA. This product is known 8 to be a t tacked by a specific cleavage enzyme to finnis...

Biotin carboxylase catalyzes the ATP-dependent carboxylation of biotin and is one component of the multienzyme complex acetyl-CoA carboxylase that catalyzes the first committed step in fatty acid synthesis in all organisms. Biotin carboxylase from Escherichia coli, whose crystal structures with and without ATP bound have been determined, has served as a model system for this component of the ac...

The 3-hydroxypropionate cycle is a new autotrophic CO(2) fixation pathway in Chloroflexus aurantiacus and some archaebacteria. The initial step is acetyl-coenzyme A (CoA) carboxylation to malonyl-CoA by acetyl-CoA carboxylase, followed by NADPH-dependent reduction of malonyl-CoA to 3-hydroxypropionate. This reduction step was studied in Chloroflexus aurantiacus. A new enzyme was purified, malon...