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R Ghosh

Publications and source records attributed to R Ghosh.

At least 127 records · Page 7Linked to original sources
PubMed1981

Purification and properties of the methanol dehydrogenase from Methylophilus methylotrophus.

1. A dye-linked methanol dehydrogenase, resembling many others from a variety of methylotrophic bacteria, was purified to homogeneity from extracts of methanol-grown Methylophilus methylotrophus. 2. The enzyme was very stable in the presence of methanol; in the absence of methanol it had a half-life of 1-2 days at 4 degrees C. 3. The value of A1% 1cm,280 was 17.5. 4. The enzyme retained bound methanol after passage through Sephadex G-25. This tightly-bound methanol slowly exchanged with free [14C]-methanol from a value of 0.27 mol of [14C]methanol/mol of enzyme after 48 h incubation at 4 degrees C to a limiting value of approx. 2.5 mol of [14C]methanol/mol of enzyme after 3 weeks incubation at 4 degrees C. 5. One mol of this enzyme reduced 89.4 mol of 2,6-dichlorophenol-indophenol (via phenazine methosulphate) in the absence of any additional methanol in the assay mixture. The source of the electrons involved in this reduction is not known.

Alcohol Oxidoreductases↗
PubMed1981

Regulatory properties of the pyruvate dehydrogenase complex of Pseudomonas aeruginosa.

The pyruvate dehydrogenase multienzyme complex of Pseudomonas aeruginosa was subjected to a steady-state kinetic analysis using the exponential model for a regulatory enzyme and a sensitive statistical fitting procedure. This showed that all the substrates, pyruvate, CoA and NAD+, exhibit cooperative kinetics towards the native multienzyme complex.

Coenzyme A↗
PubMedDate not supplied

Direct in situ structural analysis of recombinant outer membrane porins expressed in an OmpA-deficient mutant Escherichia coli strain.

An OmpA-deficient mutant of an OmpF/OmpC-free Escherichia coli B strain was selected using phage K3. The mutant strain was characterized by SDS-gel electrophoresis, immunoblotting, and electron microscopy. All major outer membrane proteins, including OmpA, were absent. This strain was then transformed with the plasmid pMY222 encoding the K12 OmpF porin or with pBlue-script-derived plasmids, encoding the porins OmpC, PhoE, and maltoporin, respectively. Following SDS extraction of outer membrane sacculi from strains expressing individual porins, crystalline porin arrays that allowed in situ structural analysis to be performed were observed. Furthermore, the absence of endogenous major outer membrane proteins facilitated the purification of native porin-lipopolysaccharide complexes, the functionally active channels, from the sacculi of transformed strains.

Bacterial Outer Membrane Proteins↗
PubMedDate not supplied

Changes in tissue levels of glutathione, extent of lipid peroxidation, and activity of glutathione peroxidase in transplantable murine lymphoma.

The reduced glutathione (GSH) levels in the hepatic tissues, extent of lipid peroxidation in the liver, kidney and brain, and alterations in the activity of glutathione peroxidase (GPX) in the hepatic tissues were monitored in mice bearing a transplantable ascitic lymphoma. These markers showed substantial alterations during the height of tumour progression when compared to controls. The GSH level, extent of lipid peroxidation, and GPX activity increased sharply after approximately 2 weeks following inoculation of ascitic cells. This was followed by a steady decline in all markers and death occurred around day 32 after inoculation.

Animals↗
PubMedDate not supplied

Vanadium: a modifier of drug-metabolizing enzyme patterns and its critical role in cellular proliferation in transplantable murine lymphoma.

Vanadium, as ammonium monovanadate, has been found to stimulate tumour cell proliferation in mice bearing a transplantable ascitic lymphoma. Markers including microsomal cytochrome P-450, UDP-glucuronyltransferase and cytosolic glutathione-S-transferase showed substantial alterations in a dose-responsive manner with vanadium administration when compared to the controls. Stimulation of tumour progression is also reflected by increased tumour cell count and decreased survival of the host.

Animals↗