Characterization of a Fatty Acid Synthetase from \u3ci\u3eCorynebacterium diphtheriae\u3c/i\u3e

A fatty acid synthetase from Corynebacterium diphtheriae has been purified to a specific activity of 450 nmoles of malonyl coenzyme A incorporated per min per mg. The enzyme is optimally active in 0.5 M phosphate buffer. C. diphtheriae appears to be the most primitive organism having a multienzyme complex for fatty acid synthesis

Clinical investigations concerning the use of Ethrane for Cesarean section

Peer Reviewe

The Identification of cis-II, I2-Methylene-2-hydroxyoctadecanoic Acid from \u3ci\u3eThiobacillus thiooxidans\u3c/i\u3e

A polar fatty acid has been observed as a component of an ornithine-containing lipid of Thiobacillus thiooxidans. A comparison of thin layer chromatographic mobilities of reference compounds to those of the natural acid and its derivatives suggested that the acid was a 2-hydroxy fatty acid. The presence of a cyclopropane function in the acid was indicated by l4e-Iabeling experiments and infrared spectroscopy. Mass spectrometry of the methyl ester and the acetylated methyl ester of the natural acid provided a molecular weight for the acid. Equivalent chain lengths were determined for the natural acid, the acid obtained by oxidative decarboxylation of the natural acid with permanganate, and the acids derived through reductive ring cleavage of the cyclopropane group in the ester of the oxidatively decarboxylated natural acid. The mass spectral data, the equivalent chain length determinations, and the permanganate oxidation study clearly indicated that the acid possessed an 18- carbon chain with a methylene bridge and a 2-hydroxyl function. The equivalent chain length determinations further suggested that the cyclopropane group had the cis configuration. Mass spectrographic analysis of the branched chain esters obtained by reductive cleavage of the ester which was in turn derived through oxidative decarboxylation of the natural acid allowed the assignment of the 11,12 position for the cyclopropane group. Based on these data, the polar acid is proposed to be cis-ll, 12-methylene-2- hydroxyoctadecanoic acid

Palmityl Coenzyme A Inhibition of Fatty Acid Synthesis

The effects of acyl-CoA derivatives (C8 to C20) on the activity of the fatty acid synthetases from yeast and Corynebacterium diphtheriae have been examined. Both enzyme systems are inhibited by the longer chain acyl thioesters (C16 to C20) and protected against this inhibition by bovine serum albumin (BSA). Identical relief from acyl-CoA inhibition is provided by the 6-0-methylglucose-containing lipopolysaccharide (MGLP), from Mycobacterium phlei. It is shown that MGLP forms a stable complex with palmitylCoA. This interaction accounts for the BSA-like effects of the polysaccharide. BSA and MGLP have two further effects on the fatty acid synthetases under study, also attributable to complex formation with palmityl-CoA. They stimulate the rate of over-all synthesis from acetyl-CoA and malonyl-CoAt and they cause a shift of the fatty acid pattern towards products of shorter chain length. The observed effects are discussed in terms of the regulation of fatty acid synthesis both with respect to rate and product composition. It is concluded that in the two microbial enzyme systems negative feedback inhibition and its relief are important control mechanisms