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Biomedical subjects

A Kaji

Publications and source records attributed to A Kaji.

At least 163 records · Page 9Linked to original sources
PubMed1971

Effect of sulfhydryl reagents on the ribosomes of Bacillus subtilis.

The effect of various sulfhydryl reagents on the ribosomes of Bacillus subtilis was studied. The 70S ribosomes were completely dissociated into 30S and 50S subunits by appropriate concentrations of p-chloromercuribenzoic acid (PCMB) and 5,5'-dithio-bis-(2-nitro-benzoic acid). The N-ethylmaleimide and iodoacetamide failed to dissociate the ribosomes even at relatively high concentrations. The rate of dissociation of ribosomes by PCMB varied with the concentration of ribosomes. A progressive decrease in the rate of dissociation was observed as the concentration of ribosomes in the reaction mixture was increased. The PCMB-induced ribosomal subunits were unable to reassociate into 70S monomers unless they were dialyzed against buffer containing beta-mercaptoethanol. On the average, four molecules of PCMB per 70S ribosome and two molecules of PCMB per each 30S and 50S subunit were bound. The number of PCMB molecules bound per ribosome did not change with increasing concentrations of PCMB, even though higher concentrations of PCMB resulted in dissociation of ribosomes into subunits.

Bacillus subtilis↗
PubMed1970

Release of tRNA from ribosomes by a factor other than G factor.

In addition to the G factor there exists another factor in the E. coli extracts which stimulates the release of tRNA from ribosomes. This factor is distinctly different from the G factor and may play a role in removing tRNA from the ribosome after the polypeptide chain termination factor has released the completed chain from the ribosome-bound tRNA.

Carbon Isotopes↗
PubMed1969

Evidence for one functional phenylalanyl-tRNA binding site on the 30S ribosomal subunit.

NH(2) terminal analysis of polyphenylalanine formed from 30S subunit-bound (14)C-phenylalanyl-tRNA suggests that there is only one site in a 30S subunit for specific binding of phenylalanyl-tRNA. Assuming that no movement of the bound phenylalanyl-tRNA takes place during association of 30S subunits with 50S ribosomal subunits, the binding site of the 30S ribosomal subunit corresponds to site 2 (-NH(2) side with respect to the growing polypeptide chain) of the two binding sites of 70S ribosomes.

Binding Sites↗
PubMed1969

Production and Properties of alpha-L-Arabinofuranosidase from Corticium rolfsii.

When Corticium rolfsii is grown under aerobic conditions in a medium containing one of several simple sugars or polysaccharides, it release alpha-L-arabinofuranosidase into the culture fluid. Araban and bran extract were found to be the most effective carbon sources in stimulating the production of the enzyme. Pectin and arabinose stimulated the production of the enzyme to a lesser degree, whereas xylose, glucose, galactose, and sucrose caused the formation of a relatively small amount of alpha-L-arabinofuranosidase. alpha-L-Arabinofuranosidase was demonstrated by its ability to hydrolyze phenyl-alpha-L-arabinofuranoside, araban, and arabinoxylan. The pH optimum of the enzyme was 2.5. At pH values of 2 to 9, the enzyme lost less than 15% of its activity during a 72-hr period at 2 C. At 70 C, its stability was greatest at pH values of 4 to 6.

Journal Article↗
PubMed1969

Production and properties of galactosidases from Corticium rolfsii.

When Corticum rolfsii was grown in a medium containing bran extract under aerobic conditions, it secreted alpha-D-galactosidase and beta-D-galactosidase into the culture fluid. Pectin also stimulated the production of these enzymes, whereas galactose, glucose, and sucrose stimulated their production to a lesser degree. C. rolfsii produced greater amounts of both enzymes than Aspergillus niger. Both galactosidases in the culture medium hydrolyzed alpha- and beta-p-nitrophenyl-D-galactosides as well as lactose, stachyose, melibiose, and raffinose. Both exhibited optimal activity at pH 2 to 4 and were quite stable under acidic conditions. alpha-Galactosidase was separated from beta-galactosidase by column chromatography.

Aspergillus↗