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Biomedical subjects

T Higashi

Publications and source records attributed to T Higashi.

At least 523 records · Page 29Linked to original sources
PubMed1970

Effects of heat treatment of electron-transport particles on bacterial oxidative phosphorylation.

The electron-transport particles from Mycobacterium phlei exhibit low levels of phosphorylation unless supplemented with soluble coupling proteins. Heat treatment of the electron transport particles for 15 min at 50 degrees C was found to result in a slight loss of oxidation and an activation of phosphorylation with NADH as substrate, while with succinate as substrate both activities increased. The heat-activated particles do not require the addition of soluble coupling factors and their level of oxidative phosphorylation is similar to that of the regular particles supplemented with the soluble coupling factors. In contrast to the lack of a requirement for the soluble coupling factors after heat activation, the heat-treated electron-transport particles require the presence of a particulate-bound coupling factor for phosphorylation. The heat-activated system, like the untreated system, was found to be sensitive to uncoupling agents.

Adenosine Triphosphatases↗
PubMed1970

The synthesis and turnover of rat liver peroxisomes. 3. The size distribution of peroxisomes and the incorporation of new catalase.

Rat liver peroxisomes have been separated according to size by zonal sedimentation. A method is described for calculating the size of the particles from their final position in the gradient. Peroxisomes seem biochemically homogeneous throughout their size distribution. 3 hr after injection of tritiated leucine, the specific radioactivity of catalase is the same in peroxisomes of different sizes, and it remains so for up to 1 wk after administration of the precursor. This observation rules out the possibility that peroxisomes have an extended period of independent growth. If individual particles maintain an independent existence, they must be formed very rapidly. The other possible explanation is that peroxisomes exchange material within the liver cell.

Animals↗
PubMed1969

Extraparticulate chain interaction between different electron transport particles.

Interaction or cross-linking between the respiratory chains of the electron transport particles of bacterial origin occurs with a mixture of active and inactive particles. Interaction between bacterial particles and liver sub-mitochondrial particles also occurs. Irradiation of the bacterial particles at 360 nanometers resulted in the destruction of quinone and consequent loss of ability of reduced nicotinamide adenine, dinucleotides to reduce cytochromes b, c(1), c, and a plus a(3). A mixture of both irradiated and untreated particles in the presence of the reduced dinucleotide resulted in the reduction of cytochromes c and a plus a(3), in an amount equivalent to the total concentration of these cytochromes in both types of particles. In contrast, the amount of cytochrome b reduced was equivalent to half the particle concentration or to that observed with the active particles alone. The rate of reduction of cytochromes c and a plus a(3) with the mixture of particles was similar to that with the active particles alone. The interaction or cross-linking between the particulate respiratory chains of bacteria or of bacterial and mammalian systems occurs after cytochrome b and before or at cytochrome c.

Animals↗