Studies on Ornithine-Ketoacid Transaminase

Katunuma, Nobuhiko; Matsuda, Yoshiko; Tomino, Ikuko

doi:10.1093/oxfordjournals.jbchem.a128027

Cited by 64 publications

(12 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Urea cycle enzymes were assayed by the methods of Saheki et al (1981), Ornithine aminotransferase (OAT; EC 2.6.1.13) were determined according to Katunuma et al (1964).…”

Section: Methodsmentioning

confidence: 99%

Abnormality of citrulline synthesis in liver mitochondria from patients with hyperornithinaemia, hyperammonaemia and homocitrullinuria

Inoue

Koura

Saheki

et al. 1987

J of Inher Metab Disea

View full text Add to dashboard Cite

“…Urea cycle enzymes were assayed by the methods of Saheki et al (1981), Ornithine aminotransferase (OAT; EC 2.6.1.13) were determined according to Katunuma et al (1964).…”

Section: Methodsmentioning

confidence: 99%

Abnormality of citrulline synthesis in liver mitochondria from patients with hyperornithinaemia, hyperammonaemia and homocitrullinuria

Inoue

Koura

Saheki

et al. 1987

J of Inher Metab Disea

View full text Add to dashboard Cite

“…The requirements for ornithine 8-transaminase activity in H. gloveri fat-body preparations are shown in Table 1. Omission of pyridoxal 5'-phosphate decreased the activity by 30-50%, which indicates that the pyridoxal derivative serves as a cofactor for the insect enzyme as it does in other species (Vogel & Kopac, 1960;Katunuma, Matsuda & Tomino, 1964;Hill & Chambers, 1967). Under the conditions used for the assay of ornithine 8-transaminase, the formation of glutamic y-semialdehyde was linear with both time of incubation (up to 60min.)…”

Section: Resultsmentioning

confidence: 98%

“…If this were true, the change in the free amino acid content of fat-body tissue might be invoked to explain the more rapid conversion of ornithine into proline in the adult. The decrease in such amino acids as valine, which inhibit ornithine 8-transaminase (Katunuma et al 1964), would effectively increase the reaction catalysed by ornithine transaminase in vivo and this increase might not be manifest by enzyme assays in vitro, where the inhibitory effect of high concentrations of free amino acids is diluted out. The decrease in the concentration of free lysine could also be expected to affect arginase in vivo: this amino acid is an effective competitive inhibitor of insect fat-body arginase (Reddy & Campbell, 1969).…”

Section: Discussionmentioning

confidence: 99%

Arginine metabolism in insects. Role of arginase in proline formation during silkmoth development

Reddy

Campbell

1969

Biochemical Journal

View full text Add to dashboard Cite

1. Ornithine 8-transaminase (L-ornithine-2-oxo acid aminotransferase, EC 2.6.1.13) and A'-pyrroline-5-carboxylate reductase [L-proline-NAD(P) 5-oxido. reductase, EC 1.5.1.2] were demonstrated in fat-body and flight-muscle tissues of the silkmoth Hyalophora gloveri. Arginase (L-arginine ureohydrolase, EC 3.5.3.1) is also present in these tissues. 2. Arginase, ornithine transaminase and pyrrolinecarboxylate reductase are generally considered to make up the catabolic pathway for the conversion of arginine into proline. The conversion of L-[U-14C]argirline into [14C]proline by intact fat-body tissue was used to show that the enzymes in insect fat body also function in this capacity. 3. Of the three enzymes of the catabolic pathway, only arginase increased during adult development and the increase coincided with the emergence of the winged adult moth. Since proline appears to be a major substrate utilized in insect flight metabolism, the increase in arginase activity at this stage suggests a major role for arginase in proline formation.

show abstract

“…OKT functions therefore in the catabolism of ornithine via glutamic acid and its conversion to proline (10,13,14). It cer tainly fulfils a major role in the regulation of orni thine pools, whereby ornithine transport into the mitochondrium is also of great importance (19).…”

Section: Discussionmentioning

confidence: 99%

Hepatic Ornithine Aminotransferase in the Rat after Portacaval Shunt

Jp¹,

Bachmann²

1980

Enzyme

View full text Add to dashboard Cite

/.-Ornithine (2-oxoacid aminotransferase, OKT) has been determined in the livers of portacaval shunt (PCS) rats, submitted to different diets, influencing blood brain amino acid transport. OKT activity was not greatly influenced by PCS. An in vivo stimulatory effect by branched chain amino acids and arginine could not be observed or confirmed by amino acid analysis in liver tissue. However, after the addition of glucose to the diet, a significant drop of OKT activity occurred.

show abstract

Studies on Ornithine-Ketoacid Transaminase

Cited by 64 publications

References 0 publications

Abnormality of citrulline synthesis in liver mitochondria from patients with hyperornithinaemia, hyperammonaemia and homocitrullinuria

Abnormality of citrulline synthesis in liver mitochondria from patients with hyperornithinaemia, hyperammonaemia and homocitrullinuria

Arginine metabolism in insects. Role of arginase in proline formation during silkmoth development

Hepatic Ornithine Aminotransferase in the Rat after Portacaval Shunt

Contact Info

Product

Resources

About