The metabolism of Prototheca zopfii was investigated in an attempt to establish the specific function of its growth factor, thiamin. A study of the oxidative decomposition of various substrates by this organism demonstrated that the addition of catalytic amounts of thiamin to vitamin-deficient cells causes a pronounced stimulation in the rate of oxygen utilization during the degradation of cert...

Two pathways have been postulated for the conversion of propionic acid to pyruvic acid by liver mitochondria. Mahler and Huennekens (1953) suggested that propionic acid was oxidized to acrylic acid which was converted to pyruvic acid through Land D-lactic acids. The alternative pathway involves a direct carboxylation of propionic acid to succinic acid (Lardy and Adler, 1956; Flavin et al., 1955...

Bloch and Rittenberg (1, 2) have reported that deuterio-nn-alanine and acetylamino acids labeled with deuterium in the acetyl group give rise to a large isotope concentration in the acetyl groups of amines containing an a-hydrogen atom, in contrast to amines not having an a-hydrogen atom. With deuterioacetic acid itself, no such difference in the acetylation of the two types of foreign amines w...

In the course of studies on the desamidation of glutamine in rat liver extracts marked acceleration of this reaction was noted in the presence of 2,4-diketovaleric acid (acetopyruvic acid) .l Recent work indicates that pyruvic acid and certain other ar-keto acids increase the desamidation of glutamine in aqueous extracts of normal and neoplastic rat liver (l-3). Investigation of the mechanism o...