Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine whether certain outer membrane proteins are associated with growth of Bacteroides thetaiotaomicron on polysaccharides, we developed a procedure for separating outer membranes from inner membranes by sucrose density centrifugation. Cell extracts in 10% (wt/vol) sucrose-10 mM HEPES buffer (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) (pH 7.4) were separated into two fractions on a two-step (37 and 70% [wt/vol]) sucrose gradient. These fractions were further resolved into outer membranes (p = 1.21 g/cm3) and inner membranes (p = 1.14 g/cm3) on sucrose gradients. About 20 to 26% of the total 3-hydroxy fatty acids from lipopolysaccharide and 2 to 3% of the total cellular succinate dehydrogenase activity were recovered in the outer membrane preparation. The inner membrane preparation contained 22 to 49% of the total succinate dehydrogenase activity and 2 to 3% of the total 3-hydroxy fatty acids from lipopolysaccharide. Outer membranes contained a lower concentration of protein (0.34 mg/mg [dry weight]) than did the inner membranes (0.68 mg/mg [dry weight]). Molecular weights of inner membrane polypeptides ranged from 11,000 to 133,000. The most prominent polypeptides had molecular weights ranging from 11,000 to 26,000. In contrast, the molecular weights of outer membrane polypeptides ranged from 17,000 to 117,000. The most prominent polypeptides had molecular weights ranging from 42,000 to 117,000. There were several polypeptides in the outer membranes of bacteria grown on polysaccharides (chondroitin sulfate, arabinogalactan, or polygalacturonic acid) which were not detected or were not as prominent in outer membranes of bacteria grown on monosaccharide components of these polysaccharides.
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PMID:Isolation and characterization of outer membranes of Bacteroides thetaiotaomicron grown on different carbohydrates. 671 79

Addition of cations (20 to 50 mM for Mg(2+) or Ca(2+) or 100 to 500 mM for Na(+)) to N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid buffer during preparation of membranes from smooth and rough strains of Salmonella typhimurium LT2, Salmonella minnesota, and Escherichia coli O8 had two effects on the composition of the membranes isolated. First, in rough strains of chemotypes Ra to Re the "total membranes" (pellets from high-speed centrifugation) were deficient in the proteins of the outer membrane. The missing proteins were found to have been sedimented in a prior low-speed centrifugation in a fraction we call "cation-aggregated membranes." Since these membranes were enriched for lipopolysaccharide and for outer membrane proteins, deficient in succinic dehydrogenase, and contained primarily the dense peak after sucrose gradient centrifugation, it appears to be relatively pure outer membrane. About 10% of the membrane protein of smooth strains and up to 50% that of rough strains were cation-aggregated membranes, appearing to contain most of the outer membrane of rough strains. Thus, cation aggregation may be a useful means of preparation of outer membrane samples. The second effect was that with cation addition, several high-molecular-weight proteins not seen when membranes were prepared without cation addition were found in the total membranes of both smooth and rough strains after high-speed centrifugation. These proteins were bound by cations to the inner membranes, since they were soluble in Triton X-100 and separated into the less dense peak upon sucrose gradient centrifugation. They originated from the cytoplasm or the periplasm, since they corresponded to soluble proteins found in the supernatant after high-speed centrifugation and were depleted from this supernatant when preparation was done in the presence of cations.
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PMID:Interactions of cations with membrane fractions of smooth and rough strains of Salmonella typhimurium and other Gram-negative bacteria. 701 32