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Biomedical subjects

J Hirose

Publications and source records attributed to J Hirose.

106 records · Page 6Linked to original sources
PubMed1983

[Clinical evaluation of serum CEA levels in uterine cervix cancer].

Serum CEA levels were measured in the blood of 98 patients with uterine cervix cancer before, during, and after treatment to investigate the relationship among the CEA level, the extent of the disease, and recovery. The CEA level rose as the disease progressed. Although there was no significant difference in the survival rates of patients with various CEA levels, those who returned to normal levels after treatment recuperated better. There was not clear evidence that CEA levels are clinically significant. However, it can be concluded that CEA levels at pre- and post-treatment times are helpful in the early detection of disease, prognosis, and in predicting recurrence or metastasis.

Carcinoembryonic Antigen↗
PubMed1981

Coordination chemical studies on metalloenzymes. IX. Properties of the ternary complex between cobalt(II)-bovine carbonic anhydrase and bidentate ligands.

The spectrum, thermodynamic parameters, and proton longitudinal relaxation time of the ternary complex between various bidentate ligands (2-pyridinecarboxylate, 2-quinolincarboxylate, 8-quinolinecarboxylate, and 2-pyridylacetate) and cobalt(II)-bovine carbonic anhydrase were measured to clarify the nature of the ternary complex. The formation constants of the ternary complexes of bidentate ligands are in the order of (2-pyridinecarboxylate approximately greater than 8-quinolinecarboxylate much greater than 2-quinolinecarboxylate approximately equal to 2-pyridylacetate). The degree of the shift of the band characteristic of five-coordinate species at 13-15 kcm-1 (cm-1 X 10(-3)) and that of the higher energy band at 21-22 kcm-1 decrease almost in the same order. These results are explained on the basis of the contribution of the bond formation between the nitrogen atom of the heterocyclic ring of ligands and cobalt ion. The formation constants of the ternary complex of bidentate ligands were compared to the stability constants of various ligands with a cobalt ion but there is no correlation in these values. The rate constant of break-up of the ternary complex was discussed on the coordination geometry of the ternary complex on the basis of the degree of the distortion.

Animals↗
PubMed1980

Metal coordination geometry of ternary complex between cobalt-bovine carbonic anhydrase and multidentate ligands.

Interaction of cobalt(II) bovine carbonic anhydrase with 3- and 4-pyridinecarboxylates, 2-pyridinecarboxylate, and 2,6-pyridinedicarboxylate has been investigated by the spectrophotometric method. The apparent formation constant of the ternary complex (ligand : cobalt ion : apoenzyme = 1 : 1 : 1) was determined from spectral data. The spectroscopic data of the ternary complex indicate that the 3- or 4-pyridinecarboxylate adduct has a five-coordination geometry through three donor atoms of the protein part of the enzyme, the carboxyl group of 3- or 4-pyridinecarboxylate, and a water molecule. 3- or 4-Pyridinecarboxylate behaves as a monodentate ligand. The spectrum of the ternary complex of 2-pyridinecarboxylate was very different from that of 3- or 4-pyridinecarboxylate. The spectra data indicate that 2-pyridinecarboxylate adduct has a five-coordination geometry and that it behaves as a bidentate ligand. The ternary complex of 2,6-pyridinedicarboxylate was so unstable that the spectrum of the ternary complex was determined by the indirect method. The spectrum of 2,6-pyridinedicarboxylate adduct shows lower molar absorption than that of 2-pyridinecarboxylate adduct. This result indicates that 2,6-pyridine dicarboxylate behaves possibly as a tridentate ligand.

Animals↗
PubMed1977

Coordination chemical studies on metalloenzymes. II. Kinetic behavior of various types of chelating agents towards bovine carbonic anhydrase.

In order to investigate the kinetics and mechanism of the removal of zinc ions from bovine carbonic anhydrase [EC 4.2.1.1] (BCA), several chelating agents with various stability constants were used to remove zinc from BCA. The second-order rate constants (kaap) of zinc removal from BCA were found to be in the following order; 2,6-pyridinedicarboxylic acid greater than 2-pyridinecarboxylic acid greater than 2,4-pyridinedicarboxylic acid greater than 2,3-pyridinedicarboxylic acid greater than or approximately 1,10-phenanthroline greater than or approximately 5-methyl-1,10-phenanthroline greater than 2,2'-bipyridine. With similar chelating agents the greater the stability constant, the faster was the rate of removal of zinc ions from BCA. With EDTA, trans-1,2-cyclohexanediaminetetraacetic acid, and nitrilotriacetic acid, the rate of zinc ion removal from the native enzyme was governed by the rate of spontaneous dissociation of zinc enzyme. The rate constants for the removal of zinc ions from BCA were governed by the affinity of the chelating agents for the metal ion and the conformation of the chelating agents. Based on these findings, reaction pathways for various chelating agents are proposed.

Animals↗
PubMed1976

Coordination chemical studies on metalloenzymes. Kinetics and mechanism of the Zn(II) exchange reaction between chelating agent and apo-bovine carbonic anhydrase.

The mechanism of removal of the zinc ion from bovine carbonic anhydrase [EC 4.2.1.1] (BCA) by a chelating agent was studied. It was shown that the removal of the zinc ion from BCA took place through the formation of a ternary complex involving the enzyme, chelating agent, and metal ions. The formation constant of the ternary complex (KEML) was 10(2) M-1. This value was lower than the formation constant assumed by Wilkins. The reaction of zinc-2, 6-pyridinedicarboxylate complex with the apoenzyme also took place through the formation of the ternary complex and the species which reacted with apo-BCA was a 1:1 complex of zinc and 2, 6-pyridine-dicarboxylate. The theoretical equilibrium equation derived from the reaction mechanism showed a good fit with observed equilibrium dialysis data.

Animals↗