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Biomedical subjects

S Stein

Publications and source records attributed to S Stein.

At least 235 records · Page 13Linked to original sources
PubMed1974

Role for heme in mammalian protein synthesis: activation of an initiation factor.

Two nonerythropoietic tissues, brian and liver, contain an initiation factor that can overcome the block in initiation of protein synthesis seen in reticulocyte lysates when exogenous hemin is not present. Upon incubation of the brain factor with hemin and removal of free hemin by gel filtration, the factor activity is strongly stimulated. This stimulation shows a concentration dependence on hemin close to that seen for stimulation of protein synthesis in whole reticulocyte lysates. The data indicate that hemin mediates the formation of an active initiation factor complex from inactive, lower molecular weight components.

Animals↗
PubMed1974

Glucose metabolism in Neisseria gonorrhoeae.

The metabolism of glucose was examined in several clinical isolates of Neisseria gonorrhoeae. Radiorespirometric studies revealed that growing cells metabolized glucose by a combination on the Entner-Doudoroff and pentose phosphate pathways. A portion of the glyceraldehyde-3-phosphate formed via the Entner-Doudoroff pathway was recycled by conversion to glucose-6-phosphate. Subsequent catabolism of this glucose-6-phosphate by either the Entner-Doudoroff or pentose phosphate pathways yielded CO(2) from the original C6 of glucose. Enzyme analyses confirmed the presence of all enzymes of the Entner-Doudoroff, pentose phosphate, and Embden-Meyerhof-Parnas pathways. There was always a high specific activity of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) relative to that of 6-phosphogluconate dehydrogenase (EC 1.1.1.44). The glucose-6-phosphate dehydrogenase utilized either nicotinamide adenine dinucleotide phosphate or nicotinamide adenine dinucleotide as electron acceptor. Acetate was the only detectable nongaseous end product of glucose metabolism. Following the disappearance of glucose, acetate was metabolized by the tricarboxylic acid cycle as evidenced by the preferential oxidation of [1-(14)C]acetate over that of [2-(14)C]acetate. When an aerobically grown log-phase culture was subjected to anaerobic conditions, lactate and acetate were formed from glucose. Radiorespirometric studies showed that under these conditions, glucose was dissimilated entirely by the Entner-Doudoroff pathway. Further studies determined that this anaerobic dissimilation of glucose was not growth dependent.

Acetates↗