Threonine catabolism in Trypanosoma brucei.

L-Threonine is catabolized by Trypanosoma brucei to give equimolar quantities of glycine and acetate. The pathway, which involves the two enzymes L-threonine dehydrogenase (EC 1.1.1.103) and aminoacetone synthase (acetyl-CoA:glycine C-acetyltransferase, EC 2.3.1.29) and subsequent hydrolysis of the acetyl-CoA, is most active in cultured trypanosomes but is also present in bloodstream forms. L-Threonine dehydrogenase from both culture and bloodstream forms of trypanosomes has an apparent molecular weight of between 28 000 and 38 000, and is sensitive to a wide range of sulphydryl reagents.