ABSTRACT
Metabolism of polyphosphoinositide was studied in bulk isolated brain cells. Cells were isolated by a rapid method using mechanical disruption followed by molecular seiving and centrifugation. Incorporation of [32Pi]orthophosphate into phosphatidyl inositol-4-phosphate and phosphatidylinositol-4,5 bis-phosphate was optimum at 30 and 60 min, respectively, in the isolated cells. Breakdown studies showed maximum loss of 32Pi after 60 min. Addition of ethanol at and above 10 mM concentration in vitro significantly decreased the incorporation of 32Pi into both phosphatidylinositol-4-phosphate and phosphatidylinositol-4,5 bis-phosphate by the isolated cells. However, the spontaneous breakdown of polyphosphoinositide was not altered in the presence of ethanol in vitro.
Subject(s)
Animals , Cell Survival/drug effects , Cells, Cultured , Cerebral Cortex/cytology , Ethanol/pharmacology , Kinetics , Phosphates/metabolism , Phosphatidylinositol 4,5-Diphosphate , Phosphatidylinositol Phosphates , Phosphatidylinositols/metabolismABSTRACT
A bacterium, utilising acrylonitrile as a sole source of carbon and nitrogen, was isolated from Indian Petrochemical Corporation Limited (IPCL) waste waters and identified as Arthrobacter sp. This strain could also utilize acetonitrile, acetamide and acrylamide individually as a source of carbon and nitrogen. The metabolic studies with the whole cells indicated the sequential conversion of the nitrile to the respective amide and then to the respective acid and ammonia. The rate of nitrile hydrolysis was slower than the corresponding amide hydrolysis. Acrylic acid, the end product of acrylonitrile breakdown, did not support the growth when provided as a carbon source.
Subject(s)
Acrylonitrile/metabolism , Bacteria/isolation & purification , Biodegradation, Environmental , Petroleum , Waste Disposal, Fluid , Water Microbiology , Water Pollutants, ChemicalABSTRACT
A phytase (EC 3.1.3.8) was extracted from rat intestinal bacterium, Klebsiella Sp. No. PG.-2, and purified 50-fold by ammonium sulphate fractionation, ion-exchange chromatography and gel filtration. The enzyme is inducible in nature. The pH optimum was at 6.0 for all the inositol phosphates studied and this characterized the enzyme as an acid phosphohydrolase. Of a range of potential substrates tested, only p-nitrophenyl phosphate alongwith the inositol phosphates was hydrolyzed. It exhibits a Km of 2.0 mM; temperature optimum of 37 degrees C and energy of activation 9,120 cal/mole for all the inositol phosphates studied. The activity was inhibited by Ag2+, Hg2+, Cu2+, fluoride and high substrate concentration.
Subject(s)
6-Phytase/isolation & purification , Klebsiella/enzymologyABSTRACT
alpha-Galactosidase has been purified from Klebsiella Sp. No. PG-2, a bacterium isolated from rat small intestine, using calcium phosphate gel, DEAE-cellulose column chromatography and gel filtration technique. About 130-fold increase in specific activity was observed, the pH optimum of 6.5-7.0 characterizes the enzyme as neutral alpha-galactosidase. The optimum temperature was 37 degrees C and the energy of activation was 11,856 cal/mole. Km values obtained for raffinose, mellibose, stachyose and p-nitrophenyl-alpha-D-galactopyranoside were 20.0, 6.6 33.3 and 4.0 mM respectively. The activity was inhibited by p-CMB; iodoacetate, Ag2+, Hg2+, Cu2+, Pb2+ and galactose. Examination of the enzyme activity indicated that the enzyme is cytosolic and is inducible in nature.