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Biomedical subjects

Y Kakimoto

Publications and source records attributed to Y Kakimoto.

At least 55 records · Page 3Linked to original sources
PubMed1983

A beta-citryl-L-glutamate-hydrolysing enzyme in rat testes.

An enzyme responsible for the deacylation of beta-citryl-L-glutamate to citrate and glutamate has been characterized in rat testis. The enzyme required manganese ion for full activity and was strongly inhibited by nucleotides such as ATP or GTP. The activity was localized in the particulate fractions. The enzyme favored N-formyl-L-glutamate greater than beta-citrly-L-glutamate greater than beta-citryl-L-glutamine in a decreasing order. The amidohydrolyase activity was highest in the testis and lung, a moderate activity was detected in heart, kidney and intestine, and low in brain, thymus, stomach, skeletal muscle, spleen and liver. These findings suggest that the amidohydrolase is different from any of amidohydrolases reported so far, amidohydrolase I (EC 3.5.1.14), II (EC 3.5.1.15), III, N-acetyl-lysine deacylase (EC 3.5.1.17) and N-acetyl-beta-alanine deacetylase (EC 3.5.1.21), and various peptidases.

Amidohydrolases↗
PubMed1982

Correlation of the level of beta-citryl-L-glutamic acid with spermatogenesis in rat testes.

beta-Citryl-L-glutamic acid, which is known to be highly concentrated in the brains of immature animals, is preferentially localized in the testes of various adult animals, including mammals, amphibians and fish, mainly in the germinal cells. In young rats, the citrylglutamate concentration increases with age and coincides with the development of late spermatocytes into early spermatids. Rats with seminiferous tubule failure induced by ductuli efferentes ligation and experimental cryptorchidism are infertile as a result of germ cell depletion, especially spermatocytes and early spermatids. In these animals, the testicular citrylglutamate content was much lower than in normal testes.

Animals↗
PubMed1982

N-acetyl-L-aspartic acid, N-acetyl-alpha-L-aspartyl-L-glutamic acid and beta-citryl-L-glutamic acid in human urine.

N-Acetyl-L-aspartic acid (NA-Asp), N-acetyl-alpha-L-aspartyl-L-glutamic acid (NA-Asp-Glu) and beta-citryl-L-glutamic acid (beta-CG), which are known to occur in the brain, have been isolated from human urine. Their identities were proved by comparing them with synthetic NA-Asp, NA-Asp-Glu and beta-CG using electrophoretic and chromatographic methods and by acid hydrolysis. A method was developed for the quantitation of NA-Asp, NA-Asp-Glu and beta-CG in human urine. It consists of ion-exchange chromatography followed by gas-chromatographic analysis. The amounts of urinary excretion of NA-Asp, NA-Asp-Glu and beta-CG were 41.2 +/- 10.1 (n = 27), 20.8 +/- 9.6 (n = 27) and 30.2 +/- 13.2 (n = 21) mumol/g creatinine in adult males, and 62.2 +/- 16.3 (n = 27), 24.0 +/- 8.2 (n = 27) and 40.5 +/- 21.1 (n = 24) mumol/g creatinine in adult females, respectively.

Adult↗
PubMed1981

A gas chromatographic method for the determination of N-acetyl-L-aspartic acid, N-acetyl-alpha-aspartylglutamic acid and beta-citryl-L-glutamic acid and their distributions in the brain and other organs of various species of animals.

A simple and sensitive gas-chromatographic method for the determination of N-acetyl-L-aspartic acid (NA-Asp), N-acetyl-alpha-aspartylglutamic acid (NA-Asp-Glu) and beta-citryl-L-glutamic acid (beta-CG) was developed. The organ, regional and phylogenetic distributions of these compounds were studied. NA-Asp and NA-Asp-Glu were highly concentrated in nervous tissue, and less than 1% of the amounts in the nervous tissues were found in non-nervous organs. These two compounds showed a reciprocal relationship in their regional distribution in mature brains, but such a relationship was not evident or was even reversed in immature brains. The two compounds also showed different developmental changes in different regions of the brain. Fish brain contained a relatively high concentration of NA-Asp, but only a trace amount of NA-Asp-Glu. By contrast, a 10 times higher concentration of NA-Asp-Glu than NA-Asp was found in frog brain. Reptilian brain contained similar amounts of each compound. Avian and mammalian brain had NA-Asp at a roughly 10 times higher concentration than NA-Asp-Glu. beta-CG occurred at the highest concentration in the immature brain of rat and guinea pig, but disappeared in the mature brains. The adult frog brain, however, contained a large amount of beta-CG. In the adult rat, testis contained the highest concentration of beta-CG.

Aging↗
PubMed1981

Developmental changes of N-acetyl-L-aspartic acid, N-acetyl-alpha-aspartylglutamic acid and beta-citryl-L-glutamic acid in different brain regions and spinal cords of rat and guinea pig.

The developmental changes of N-acetylaspartic acid (NA-Asp), N-acetyl-alpha-aspartylglutamic acid (NA-Asp-Glu), and beta-citryl-L-glutamic acid (beta-CG) have been examined in the cerebrum, cerebellum, brain stem and spinal cord of both rat and guinea pig by the gas chromatographic method developed in our studies. A rapid increase in the concentration of NA-Asp was observed postnatally in every region of the rat brain. On the other hand, all regions of guinea pig brain showed the prenatal increases. NA-Asp-Glu showed a different developmental profile, depending on region of the brain, in the two species. The concentration of NA-Asp-Glu remained constantly low during brain maturation in the rostral regions. In the caudal portions it showed a marked increase during maturation and reached a high level in the adult brain. The concentration of beta-CG was highest at birth in all regions of rat brain and rapidly decreased by 20 days after birth and remained low thereafter. The rapid decrease occurred in the guinea pig during the foetal period, and beta-CG content decreased to an adult level at birth.

Aging↗
PubMed1979

Sex difference in the accumulation of D-beta-aminoisobutyrate in organs of mouse after thymine loading.

The concentration of D-beta-aminoisobutyric acid (D-BAIB) in the liver and kidney was twice as high and dropped more slowly in the female mouse than in the male after an intraperitoneal injection of thymine. The concentration of beta-alanine, formed from uracil by the same enzyme system catalyzing formation of D-BAIB from thymine, was not different in the liver and kidney of both sexes after an intraperitoneal injection of uracil. After the intraperitoneal injection of D-BAIB, the concentration of BAIB in male liver decreased faster than that in female liver. Inhibition of D-BAIB: pyruvate aminotransferase caused by injection of D-cycloserine resulted in a significant increase in the concentration of BAIB in liver of both sexes after injection of thymine, but the concentration dropped more rapidly in the male. The activity of D-BAIB: pyruvate aminotransferase was not different in the livers of male and female mice. Under the action of probenecid, an inhibitor of active transport systems, the sex difference in accumulation and disappearance of the amino acid in the liver was not observed. This suggested that the excretion of BAIB is more active in the renal tubules of the male mouse than in those of the female. However, the amount of BAIB excreted in the urine after injection of thymine was larger in the female mice than in the male mice. There may be another probenecid-sensitive enzyme for the disposal of BAIB in male mice.

Aminoisobutyric Acids↗
PubMed1979

Decrease of 3-methylhistidine and increase of NG,NG-dimethylarginine in the urine of patients with muscular dystrophy.

The amounts of 3-methylhistidine, N epsilon,N epsilon-dimethyllysine, N epsilon, N epsilon, N epsilon-trimethyllysine, NG,NG-dimethylarginine, and NG,N'G-dimethylarginine were determined in the urine specimens of healthy subjects and patients of corresponding ages with Duchenne, limb-girdle, and congenital types of muscular dystrophy, and motor neuron diseases. The amount of excretion of 3-methylhistidine decreased and that of NG,NG-dimethylarginine increased significantly in Duchenne and limb-girdle types of muscular dystrophy, but not in diseases with neurogenic muscular atrophy. The decrease of 3-methylhistidine was observed consistently throughout the course of the Duchenne type of muscular dystrophy. The amounts of the other methylamino acids both in myogenic and neurogenic myopathies were not different from those in healthy subjects.

Adolescent↗
PubMed1978

Isolation and identification of beta-citryl-L-glutamic acid from newborn rat brain.

An unknown compound containing glutamic acid residue was found in newborn rat brain. The compound occurred predominantly in brain. Its concentration was approx. 1 mumol/g tissue at birth and decreased to one-tenth 24 days after birth. The compound was isolated from newborn rat brains, and subjected to elementary analysis and to infrared and mass spectrometric analysis. Glutamic acid and citric acid were formed from the compound on acid hydrolysis. The compound was presumed to be a citrylglutamic acid. Two isomers, alpha- and beta-citrylglutamic acid, were synthesized. The unknown compound was identified as beta-citryl-L-glutamic acid. The occurence of this compound has not been reported in nature.

Animals↗
PubMed1976

Synthesis and degradation of methylated proteins of mouse organs: correlation with protein synthesis and degradation.

L-(Methyl-14C)-methionine was administered i.p. to mice, and the incorporation of radioactive methionine into proteins and methyllysine and methylarginine residues formed by the transfer of the methyl-14C group of methionine were measured. Tissue protein was actively methylated in organs having a high activity of protein synthesis, and the in vivo methylating activity in organs was not correlated with theprotein methylating activity of the organs determined in vitro. Puromycin inhibited both protein synthesis and protein methylation in mouse organs to a similar degree. Neither the formation of S-adenosyl-(methyl-14C)-methionine nor protein methylase was inhibited by puromycin. The data suggests that proteins are methylated immediately after protein synthesis, that is, newly synthesized proteins are the substrates of protein methylation. Radioactive methionine and the [C14] methyl groups of methyllysine and methylarginine residues of tissue proteins are degraded in parallel over a period of 3 wk, suggesting that protein methylation is an irreversible type of protein modification.

Animals↗