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Biomedical subjects

S Banerjee

Publications and source records attributed to S Banerjee.

At least 577 records · Page 32Linked to original sources
PubMed1982

Peptide mapping studies of the chromogranins and of two chromaffin granule proteoglycans.

The chromogranins, a family of related acidic glycoproteins, and two chondroitin sulfate/dermatan sulfate proteoglycans were isolated from the soluble contents of bovine adrenal chromaffin granules by chromatography on DEAE-cellulose. These chromaffin granule matrix glycoconjugates were treated with trypsin, and the resulting peptides were fractionated by HPLC. The two proteoglycans, which differ in their concentration of glycosaminoglycans and glycoprotein oligosaccharides, yielded almost identical peptide patterns and would both appear to have the same protein moiety. The peptide profile of the proteoglycans differs, however, from that of the chromogranins, which they closely resemble in terms of amino acid composition. The various chromogranin fractions obtained by gel filtration were also found to have significant differences in the chromatographic patterns of their tryptic peptides.

Adrenal Medulla↗
PubMed1981

Tobacco mosaic virus protein induces fusion of liposome membranes.

The fusogenic properties of tobacco mosaic virus (TMV) coat protein were investigated. Tobacco mosaic virus protein induces membrane fusion of a population of L-alpha-dimyristoylphosphatidylcholine (DMPC) and DL-alpha-dipalmitoylphosphatidylcholine (DPPC) vesicles giving rise to larger particles as seen by a drastic absorbance increase of the liposomal solution. Differential scanning calorimetry spectra demonstrate complete mixing of the acyl chains of the lipids during fusion. Electron micrographs indicate that the fused entities are multilamellar.

Calorimetry, Differential Scanning↗
PubMed1981

Metabolism of sitosterol by a Pseudomonas species.

Fermentation of sitosterol by a Pseudomonas species (SK-25) resulted in the formation of 5-stigmastene-3 beta, 7 alpha-diol; 5,6 alpha-epoxy-5 alpha-stigmastan-3 beta-ol; 5,6 beta-epoxy-5 beta-stigmastan-3 beta-ol and 5 alpha-stigmastan-3 beta, 5,6 beta-triol. The metabolites were characterized by a variety of conventional chemical and spectrometric techniques.

Chemical Phenomena↗
PubMed1980

Microsome-mediated covalent binding of 1,2-dichloroethane to lung microsomal protein and salmon sperm DNA.

In order to determine whether the covalent binding of the carcinogen 1,2-dichloroethane to macromolecules is dependent on microsomes or cytosol, microsomes and cytosol from lungs of C57BL/6 X C3H/He F1 (hereafter called B6C3F1) mice and Osborne-Mendel rats were incubated with [1,2-14C]dichloroethane and salmon sperm DNA. 1,2-Dichlorothane binds covalently to microsomal protein and DNA only in the presence of microsomes, whereas cytosol has insignificant metabolic activation. The binding to macromolecules was significantly higher in the presence of native microsomes than denatured microsomes. The interaction of 1,2-dichloroethane with DNA was enhanced following pretreatment of the animals with phenobarbital and 3-methylcholanthrene. On the other hand, glutathione reduced the binding. The binding of 1,2- dichloroethane to lung microsomal protein of B6C3F1 mice and to DNA was three and five times higher, respectively, than that of Osborne-Mendel rat lung microsomal proteins. 1,2-Dichloroethane interacts 85% and 100% more with protein and DNA, respectively, in the presence of microsomes obtained from lung than from liver of B6C3F1 mice. These results suggest a correlation between the microsomally mediated binding and species and organ susceptibility to 1,2-dichloroethane-induced tumorigenesis.

Animals↗
PubMed1979

Binding of carcinogenic halogenated hydrocarbons to cell macromolecules.

Ethylene dibromide (EDB), a known stomach carcinogen, and ethylene dichloride (EDC), which is carcinogenic to the liver, have been shown in in vitro experiments to bind covalently to stomach and hepatic microsomal proteins and to salmon sperm DNA. The binding of EDB or EDC with proteins was not significant when denatured microsomes were used or when DNA was used in the absence of microsomes. The binding of EDB to these macromolecules was augmented with increasing concentrations of microsomes. SKF-525A, an inhibitor of the microsomal metabolism of various substrates, significantly inhibited the binding of EDB to protein and DNA. These findings suggest that metabolic activation of EDB and EDC is required for their covalent binding to macromolecules. Glutathione and 1-methyl-2-mercaptolmidazole markedly decreased the binding of EDB, which indicated that a reactive electrophilic intermediate(s) of EDB is (are) involved in the binding. The binding of EDC to liver proteins of (C57BL/6 X C3//He)F1 mice, which are susceptible to liver tumor induction by EDC and to DNA, was significantly higher than the corresponding binding for Osborne-Mendel rats, a species not susceptible to liver tumor induction by this compound.

Animals↗
PubMed1978

Thermodynamic studies on the binding of adenosine diphosphate and calcium to beef cardiac myosin.

Thermodynamic quantities for the binding of MgADP, CaADP and Ca2+ to purified beef cardiac myosin have been determined by flow calorimetry at 25 degrees C and by equilibrium dialysis at 4 degrees C in 0.5 M KCl, 20 mM tris-HCl (pH 7.5). About 1.65 +/- 0.15 mol MgADP and 1.9 +/- 0.1 mol CaADP were bound per mol myosin. Free energies of binding of MgADP and CaADP were -6.7 and -5.7 kcal/mol, respectively. Enthalpies for binding of MgADP and CaADP were about -12.5 and -19.0 kcal/mol, respectively. Furthermore, there were 1.8 +/- 0.2 mol high affinity Ca2+ binding sites per mol myosin with an affinity constant of about 10(5) M-1. The enthalpy of Ca2+ binding was about zero. It is concluded that CaADP binds to cardiac myosin with a much greater negative enthalpy than MgADP. Also, the free energy of MgADP binding to cardiac myosin is similar to values reported for skeletal myosin. However, the enthalpy of binding is much less negative than the value obtained for skeletal myosin by Kodama and Woledge (J. Biol. Chem. (1976) 251, 7499--7503). The latter results suggest a subtle difference in the nucleotide binding sites of these myosins.

Adenosine Diphosphate↗