Kinamycin acetyltransferase I from Streptomyces murayamaensis, an apparently large, membrane-associated enzyme.

Identification and initial characterization of an apparently large, membrane-associated multifunctional enzyme, kinamycin acetyltransferase I (KAT I), is described. KAT I activity was enriched 29-fold over the level in cell-free extracts of Streptomyces murayamaensis. Two acetyltransferase activities catalyzing acetyl coenzyme A dependent conversion of kinamycin F and E to kinamycin E and D, respectively, were inseparable in the course of the partial purification. Partial purification involved separation of KAT I from cytosolic proteins by differential ultracentrifugation, solubilization with 0.5% CHAPS zwitterionic detergent followed by ultracentrifugation, and Sephacryl S400 gel filtration chromatography of the resulting supernatant.

Response of immature baboon fetal lung to intra-amniotic betamethasone.

Intra-amniotic betamethasone (6 mg.) given to six immature fetal baboons, at four and again at three days prior to delivery by cesarean section, between 147 and 158 days' gestation (term = 180 days), significantly increased the amniotic fluid lecithin/sphingomyelin (L/S) ratio. At delivery, treated animal lungs were more mature in that they had a significantly increased deflation stability and significantly decreased minimum surface tension in minced lung when compared to five control animals. Changes in maximum air distensibility lagged behind changes in deflation stability. The major molecular species of pulmonary phosphatidylcholine were analyzed by gas liquid chromatography as the diacylglycerol derivatives. The proportions of 14:0/16:0, 16:0/16:0, and 16:0/18:0, were significantly increased over control proportions while unsaturated species tended to decrease in animals exposed to intra-amniotic betamethasone. The immature fetal baboon pulmonary system responded to intra-amniotic betamethasone with a synchronous increase in the L/S ratio, improved pulmonary stability, and a more mature pulmonary lecithin composition, but did not demonstrate a synchronous increase in tissue distensibility.

The analysis of the molecular species of fetal rabbit lung phosphatidylcholine by consecutive chromatographic techniques.

The major molecular species of pulmonary phosphatidylcholine in the fetal rabbit were analyzed as the diacylglycerol acetate derivatives. After fractionation by Ag+ thin-layer chromatography according to the degree of unsaturation, the intact diacylglycerol acetates were analyzed by gas-liquid chromatography to obtain the carbon number composition. The methyl esters of these acetates were used to obtain the fatty acid profiles. The composition of the molecular species was derived from these sets of data. The proportions of 16 : 0/16 : 0, 14: 0/16 : 0 and 16 : 0/16 : 1 increased with gestation, while 16 : 0/18 : 1 decreased. The concentration of 16 : 0/16 : 0 increased about 50% the last two days of gestation while 16 : 0/16 : 1 increased about 300%. The possibility that 16 : 0/16 : 1 is a precursor of 16 : 0/16 : 0 via biohydrogenation is discussed.