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Biomedical subjects

D R Rao

Publications and source records attributed to D R Rao.

At least 55 records · Page 3Linked to original sources
PubMed1981

Enzymological and biochemical changes produced by mercuric chloride in a teleost fish, Channa punctatus.

Alterations in the activities of lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in the brian, gills, intestine, kidney, liver and muscles, the levels of glycogen and lactic acid in liver and muscles, and blood glucose have been examined in a fresh-water teleost fish, Channa punctatus after exposure to a sublethal concentration (3 microgram/1) of mercuric chloride for 15, 30 and 60 days. The results revealed that the activities of all the three dehydrogenases were inhibited significantly after 60 days of treatment except for lactate dehydrogenase in brain. Glycogen and lactic acid contents of the liver and muscles and the blood glucose level also decreased significantly after 60 days of exposure. Though gills and muscles showed weak activity of the three dehydrogenases, the percentage of inhibition was more marked in these tissues than in others.

Animals↗
PubMed1976

Activity of lipoprotein lipase in adipose tissues from steers.

Mean lipoprotein lipase activities (mueq fatty acids released/h per g tissue) and lipid content(%) in adipose tissue of steers from brisket, perirectal, subcutaneous abdominal, and mesenteric areas were 32, 32, 30, 50, and 73, 77, 64, and 85. The enzyme activity was higher in mesenteric tissue than in the other sites which did not differ from each other. Mesenteric adipose tissue had higher and subcutaneous abdominal adipose tissue had lower lipid content than did brisket and perirectal adipose tissue. Lipid content and enzyme activity were correlated .38.

Abdomen↗
PubMed1975

Studies on a 2,3-diaminopropionate: ammonia-lyase from a Pseudomonad.

2,3-Diaminopropionate:ammonia-lyase, an induced enzyme in a Pseudomonas isolate, has been purified 40-fold and found to be homogeneous by disc gel electrophoresis and by ultracentrifugation. Some of its properties have been studied. The optimum pH and temperature for activity are 8 and 40 degrees C, respectively. The enzyme shows a high degree of substrate specificity, acting only on 2,3-diaminopropionate; the D-isomer is only one-eighth as effective as the L-form. L-Homoserine and DL-cystathionine are not substrates, and 3-cyanolalanine does not inhibit its activity. It is a pyridoxal phosphate enzyme which requires free enzyme sulphhydryls for activity. The Km values for L-2,3-diaminopropionate and pyridoxal phosphate are 1mM and 25 muM, respectively. The molecular weight of the enzyme is about 80 000 as determined by gel filtration. On treatment with 0.5M urea or guanidine by hydrochloride, the enzyme dissociates into inactive subunits with an approximate molecular weight of 45 000. One mole of the active enzyme binds one mole of pyridoxal phosphate. The bacterial enzyme seems to be quite different in many of its properties from the rat liver enzyme which also exhibits the substrate specificity of cystathionine gamma-lyase.

Amino Acids, Diamino↗
PubMed1975

Effect of cell density on lactose synthesis in bovine mammary cell cultures.

The ability to synthesize lactose was studied in despersed cell cultures of lactating bovine mammary tissue under conditions of varying cell density, time, glucose, and lactose concentrations. The observable rate of lactose synthesis at a given time in an adequate medium is dependent on individual animal, length of time in culture, and density of cells. Rate of loss with time in the ability to synthesize lactose followed first order kinetics (half-time 11 h). Rate of synthesis per cell at a given time was an inverse function of the cell density following a linear relationship expressed by plotting the inverse of the amount accumulated versus the inverse of the cell number. A cell density for such experimental studies of about 2.5 times 10-6 cells per ml was ideal. The medium concentration of lactose and, above a minimum, that of glucose did not affect production of lactose.

Animals↗
PubMed1971

Enzymic synthesis of N-acetyl-L-phenylalanine in Escherichia coli K12.

1. Cell-free extracts of Escherichia coli K12 catalyse the synthesis of N-acetyl-l-phenylalanine from acetyl-CoA and l-phenylalanine. 2. The acetyl-CoA-l-phenylalanine alpha-N-acetyltransferase was purified 160-fold from cell-free extracts. 3. The enzyme has a pH optimum of 8 and catalyses the acetylation of l-phenylalanine. Other l-amino acids such as histidine and alanine are acetylated at slower rates. 4. A transacylase was also purified from E. coli extracts and its substrate specificity studied. 5. The properties of both these enzymes were compared with those of other known amino acid acetyltransferases and transacylases.

Acetates↗