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Biomedical subjects

T Tachiki

Publications and source records attributed to T Tachiki.

At least 19 recordsLinked to original sources
PubMed1991

Production and localization of enzymes on soft gel cultivation.

Production and localization of glutaminase and leucine aminopeptidase (LAP) in soft gel cultivation were compared with those in koji and liquid cultivations. The enzymes were detected only in the whole-mycelial-mat fraction by soft gel cultivation, but in both intracellular and extracellular fractions by the other two methods. The enzyme species of glutaminase and LAP in soft gel cultivation were analyzed by ion exchange and gel filtration column chromatographies. Three species of glutaminase and four (or five) species of LAP were formed in the whole-mycelial-mat fraction. The intracellular and extracellular fractions of the koji and liquid cultivations contained different species of enzymes.

Agar↗
PubMed1987

A rapid assay method for ammonia using glutamine synthetase from glutamate-producing bacteria.

A rapid enzymatic assay method for ammonia was developed by using glutamine synthetase from glutamate-producing bacteria together with pyruvate kinase, lactate dehydrogenase, and NADH. The time required for determination of 25 nmol of ammonia was 5 min with 1 unit of glutamine synthetase, as opposed to 14-30 min with 1 unit of glutamate dehydrogenases from various sources. The present method was used to determine ammonia in serum, microbiol-culture broth, and waste water. The method can be modified for spectrophotometry in the visible region by substituting pyruvate oxidase, peroxidase, and appropriate chromogens for lactate dehydrogenase and NADH. With 4-aminoantipyrine (4AA) and phenol, and with 4AA and N-ethyl-N-2-hydroxyethyl-m-toluidine as chromogens, the sensitivity of ammonia determination was 0.65 and 1.7 times that with glutamate dehydrogenase, respectively. The present method was also applicable to the continuous detection of the activity of some ammonia-forming enzymes such as guanase, adenosine deaminase, and urease and to the determination of 0.5-30 microM ATP-ADP after some modification of the mixture.

Adenosine Diphosphate↗
PubMed1984

[Experimental study on the optimal potassium and magnesium concentrations in the cardioplegic solution].

Minimum concentration of potassium and magnesium in cardioplegic solution to get cardiac arrest was studied. The isolated rat hearts were perfused by Langendorf perfusion with Modified Krebs-Henseleit bicarbonate buffer solution, and their heart rates were measured. The perfusion of infusate of 15 mM per liter of K-aspartate stopped the heart beat completely, and as the same way it was necessary 25 mM per liter of MgCl2 to get cardiac arrest. By their combination, however, heart was arrested with infusate of 10 mM per liter of K-aspartate and 15 mM per liter of MgCl2, which were lower concentration than K-aspartate or MgCl2 alone. In order to determine the optimal concentration of potassium and magnesium in cardioplegic solution, the isolated rat hearts were preserved in relatively disadvantageous condition; such as 37 degrees C of infusates, non-oxygenation, continuous perfusion and perfusion pressure 50 cmH2O during 120 minutes. Sixty isolated rat hearts were divided into eleven groups. Each group received a different proper combination of KCl (5.9, 15, 25, 40, 60 mM/L) and MgCl2 (1.2, 13, 25, 33, 50 mM/L) in cardioplegic solution. Using the isolated working rat heart apparatus, hemodynamic indices after 120 minutes preservation were compared with control values of the same hearts, and their percent recoveries were compared with one another. In conclusion it appears that in the isolated working heart model combination of KCl 40 mM/L and MgCl2 13 mM/L in Basic-Modified-Krebs-Solution might offer the best myocardial protection of all combinations tested.

Animals↗
PubMed1980

Purification, properties and formation of arginine-alpha-ketoglutarate transaminase in Arthrobacter simplex.

Arginine-alpha-ketoglutarate transaminase was purified 460-fold with 1.4% yield from Arthrobacter simplex grown on arginine as a carbon source. The preparation was more than 90% pure on polyacrylamide gel electrophoresis, and the molecular weight of the enzyme was calculated to be 110 000. The enzyme exhibited absorption maxima at 280, 330 and 370 nm. The 370 nm peak decreased with increase in the 330 nm peak on addition of arginine Km values for arginine, alpha-ketoglutarate, glutamate and alpha-keto-delta-guanidinovalerate were 2.9, 8.1, 25 and 0.30 mM, respectively. Those for pyridoxal 5'-phosphate and pyridoxamine 5'-phosphate were 0.25 and 0.57 microM. The enzyme reacted optimally at pH 8.0--8.5. The synthesis of arginine-alpha-ketoglutarate transaminase was inducible by arginine and alpha-keto-delta-guanidinovalerate.

Arthrobacter↗
PubMed1976

Resolution and complementation of the labile L-leucine-pyruvate transaminase. An intermediate during enzyme formation under nitrogen starvation in Gluconobacter suboxydans.

L-Leucine-pyruvate transaminase (mol. wt. 70 000) in Gluconobactersuboxydans synthesized during nitrogen starvation contained a labile form which changed to the stable one later. The labile enzyme (mol. wt. 70 000) dissocated to the two proteinaceous components: a cationic one (mol. wt. 10 000--20 000) and an anionic one (mol. wt. 50 000--60 000), during column chromatography on DEAE-cellulose. The enzyme activity was reconstructed when they were mixed. The reconstructed enzyme had almost the same molecular size and enzymatic properties as the labile and the native stable enzymes.

Drug Stability↗
PubMed1975

Further characterization of L-leucine-pyruvate transaminase from Acetobacter suboxydans.

L-Leucine-pyruvate transaminase obtained from Acetobacter suboxydans exhibited absorbance maxima to 280 and 332 nm. The 332 nm peak was derived from the coenzyme bound to the enzyme protein with the epsilon NH2 of a lysine residue. The transaminase showed reactivity against many L-amino acids. The relation between the reactivity and the structure of the amino donor is discussed. The Michaelis constants for L-leucine, pyruvate, L-alanine and alpha-ketoisocaproate were 6.7, 3.1, 7.1 and 0.9 mM, respectively. The equilibrium constant was 5.3. The activation energy at pH 5.0 was 8,800 cal/mol.

Acetobacter↗