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J K Bhattacharjee

Publications and source records attributed to J K Bhattacharjee.

68 records · Page 4Linked to original sources
PubMed1973

Biosynthesis of glutamic acid in Saccharomyces: accumulation of tricarboxylic acid cycle intermediates in a glutamate auxotroph.

Aconitaseless glutamic acid auxotroph MO-1-9B of Saccharomyces grew in glutamic acid-supplemented minimal medium, but failed to grow when glutamic acid was substituted by proline, arginine, ornithine, or glutamine. This mutant was also unable to utilize lactate or glycerol as a carbon source. Under a glutamic acid-limiting condition, by using acetate-1-(14)C as tracer, the mutant accumulated rather large amounts of (14)C-citric acid and (14)C-succinic acid when compared with the wild-type strain. Under excess glutamic acid supplementation, accumulation of citric acid and succinic acid was considerably reduced. When (14)C-glutamic acid-(U) was used as tracer, (14)C-alpha-ketoglutaric acid, (14)C-citric acid, and (14)C-succinic acid were accumulated in the mutant. The citric acid peak was the largest, followed by alpha-ketoglutaric acid and succinic acid. In the wild-type strain under similar conditions, only small amounts of (14)C-citric acid and (14)C-succinic acid and no (14)C-alpha-ketoglutaric acid were accumulated.

Acetates↗
PubMed1971

Lysine biosynthesis in Saccharomyces. Conversion of -aminoadipate into -aminoadipic -semialdehyde.

The reduction of alpha-aminoadipate to alpha-aminoadipic delta-semialdehyde by a cell-free extract of Saccharomyces is shown to be a three-step process. First the amino acid reacts with ATP to form an adenylyl derivative. Then the adenylyl derivative of alpha-aminoadipate is reduced in the presence of NADPH. In the third step the reduced adenylyl derivative of the amino acid is cleaved to form alpha-aminoadipic delta-semialdehyde. The presence of Mg(2+) is necessary for the first and second steps. The third step does not need any cofactors. The product of the first step was isolated by chromatography after incubating the cell-free extract of Saccharomyces with alpha-aminoadipate, ATP and Mg(2+). The isolated product was identified as an adenylyl derivative of alpha-aminoadipate and could be converted into alpha-aminoadipic delta-semialdehyde under the stated experimental conditions. The product of the second step was too unstable to be identified.

Adenosine Triphosphate↗
PubMed1971

Effect of hydroxylysine on the biosynthesis of lysine in saccharomyces.

Hydroxylysine acts as a growth inhibitor of Saccharomyces for a certain period of time. The inhibition is concentration-dependent and is reversed by a small amount of lysine in the medium. After the growth-inhibitory period, the wild-type cells are able to grow rapidly even in the presence of hydroxylysine. Both lysine auxotrophs and wild-type cells are unable to utilize hydroxylysine in place of lysine. Hydroxylysine, mimicking lysine, controls the biosynthesis of lysine and thereby limits the availability of biosynthetic lysine to the cells. Hydroxylysine affects the biosynthesis of lysine at a number of enzymatic steps. Accumulation of homocitric acid, the first intermediate of lysine biosynthesis, in the mutant strains 19B and A B9 is reduced significantly in the presence of hydroxylysine. Hydroxylysine, like lysine, exerts a significant inhibition in vitro on the homocitric acid-synthesizing activity. Enzymes following the alpha-aminoadipic acid step respond in a noncoordinate fashion to hydroxylysine. Level of the enzyme saccharopine reductase, but not of alpha-aminoadipic acid reductase or saccharopine dehydrogenase, is reduced significantly. These regulatory effects of hydroxylysine are similar to those observed for lysine.

Adipates↗
PubMed1968

Identification of malic acid from yeast.

Evidence indicated an accumulation of l-malic acid in the synthetic growth medium of both lysine auxotrophs and wild-type yeast. Malic acid was isolated from growth experiments and was identified by paper and column chromatography, by comparison of infrared spectra with authentic l-malic acid, as well as enzymatically, as a substrate of malic dehydrogenase. Malic acid was accumulated when glucose was used as a carbon source. This did not occur when sodium lactate was the carbon source. Malic, succinic, and citric acids, and a few other as yet unidentified organic acids, were accumulated in the culture supernatant fluid when yeast was grown in a chemically defined medium. The accumulation of these acids had no obvious relation to the pathway for lysine biosynthesis.

Acetates↗