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Biomedical subjects

Y Tani

Publications and source records attributed to Y Tani.

At least 289 records · Page 16Linked to original sources
PubMed1981

Syntheses of L-tyrosine-related amino acids by tyrosine phenol-lyase of Citrobacter intermedius.

Degradation of tyrosine to phenol, pyruvate and ammonia by tyrosine phenol-lyase from Citrobacter intermedius (formerly named Escherichia intermedia) is readily reversible at high concentrations of pyruvate and ammonia. Spectrophotometric studies indicate that ammonia is the first substrate which interacts with bound pyridoxal 5'-phosphate. Kinetic results show that pyruvate is the second substrate bound, hence phenol must be the third. When an appropriate phenol derivative is substituted for phenol, the corresponding tyrosine analogue can be synthesized. 3-Fluoro-, 2-fluoro-, 3-chloro-, 2-chloro-, 3-bromo-, 2-bromo-, 2-iodo-, 3-methyl-, 2-methyl- and 2-methoxy-L-tyrosines have been synthesized by this reaction. By using various phenol derivatives or tyrosine analogues as substrates, the substrate specificity of tyrosine phenol-lyase is investigated and the situation of its active site is discussed.

Citrobacter↗
PubMed1980

Purificaton and characterization of S-formylglutathione hydrolase from a methanol-utilizing yeast, Kloeckera sp. No. 2201.

S-Fromylglutathione hydrolase (EC 3.1.2.12), a glutathione thiol esterase, was purified from a methanol-utilizing yeast, Kloeckera sp. No. 2201, to homogeneity as judged by polyacrylamide gel electrophoresis. The molecular weight of the native enzyme was determined to be 58 000 by gel filtration. The enzyme appeared to be composed of two identical subunits (Mr = 31 000). The apparent Km for S-formylglutathione was 0.077 mM. The optimum temperature was 50 degrees C and the optimum pH was 6.4-6.6. The enzyme was inhibited by several types of sulfhydryl reagents. The purified enzyme preparation contained no activity of formaldehyde dehydrogenase or of formate dehydrogenase. It is thought that three enzymes, formaldehyde dehydrogenase, S-formylglutathione hydrolase and formate dehydrogenase, participate in the oxidation of formaldehyde to CO2 in Kloeckera sp. No. 2201.

Carboxylesterase↗
PubMed1980

Purification and characterization of polyethylene glycol dehydrogenase involved in the bacterial metabolism of polyethylene glycol.

Polyethylene glycol (PEG) dehydrogenase in crude extracts of a PEG 20,000-utilizing mixed culture was purified 24 times by precipitation with ammonium sulfate, solubilization with laurylbetaine, and chromatography with diethylamino-ethyl-cellulose, hydroxylapatite, and Sephadex G-200. The purified enzyme was confirmed to be homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of the enzyme, which appeared to consist of four identical subunits, was 2.4 X 10(5). The enzyme was stable below 35 degrees C and in the pH range of 7.5 to 9.0. The optimum pH and temperature of the activity were around 8.0 and 60 degrees C, respectively. The enzyme did not require any metal ions for activity and oxidized various kinds of PEGs, among which PEG 6,000 was the most active substrate. The apparent Km values for tetraethylene glycol and PEG 6,000 were about 10.0 and 3.0 mM, respectively.

Alcohol Oxidoreductases↗