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Biomedical subjects

M Kuwada

Publications and source records attributed to M Kuwada.

At least 19 recordsLinked to original sources
PubMed2001

Purification of cytochromes P-450(scc) and P-450(17 alpha) by steroid-binding affinity column chromatography.

The preparation, testing and use of a variety of cholesterol-, deoxycorticosterone (DOC)- and pregnenolone-binding 1,6-diaminohexyl (EAH)-Sepharose 4B supports for affinity column chromatography of cytochromes P-450(scc) and P-450(17 alpha) from bovine adrenal and pig testis are described. EAH-Sepharose 4B has free amino groups at the end of a 10-atom spacer arm. Hydroxyl groups of cholesterol (3 beta), deoxycorticosterone (21 beta) and pregnenolone (3 beta) are linked to succinic anhydride in pyridine through an ester linkage. These coupling ligands of hemisuccinate were synthesized by a general procedure. Free amino groups of EAH-Sepharose 4B were used to couple ligands, containing carboxyl groups, by the carbodiimide coupling method. Both the purified cytochromes P-450(scc) and P-450(17 alpha) were found to be homogeneous and estimated to have a molecular weight of 52,000 on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The carbon monoxide difference spectra with peaks at 450 and 448 nm exhibit the absorption spectra of typical cytochromes P-450(scc) and P-450(17 alpha), respectively. Cytochromes P-450(scc) and P-450(17 alpha) were determined to have isoelectric points of 8.0 and 6.5 in isoelectric focusing on a pH gradient gel. Cytochrome P-450s can be purified between 425- and 1000-fold from the crude extracts.

Adrenal Glands↗
PubMed2001

Conformational change in a single molecular species, beta3, of beta-conglycinin in acidic ethanol solution.

Several physicochemical experiments were done to obtain further information on the conformational changes occurring in beta-conglycinin in acidic-ethanol solution, using a single molecular species of this protein, beta3. By far-UV circular dichroism (CD), a transition from beta-sheet to alpha-helical structure was observed upon addition of acidic-ethanol, and the alpha-helix content was found to reach 76% in 70% ethanol (pH 2). From analyses of near-UV CD and difference absorption spectra, it was found that the tertiary structure of the beta3 species was significantly altered at ethanol concentrations between 10 and 20%. The profiles of binding of 1-anilinonaphthalene-8-sulfonic acid to the beta3 species during acidic-ethanol denaturation were indicative of the existence of intermediate conformers in the molten globule-like denaturation state. By measuring Fourier transform infrared spectra and estimating the Stokes radius by dynamic light scattering, the beta3 molecules were found to aggregate with an increase in ethanol concentration.

Anilino Naphthalenesulfonates↗
PubMed2001

[Discovery of the adult Schistosoma japonicum, a causative agent of Schistosomiasis in the Katayama area of Hiroshima Prefecture].

People in the Katayama area of Hiroshima Prefecture had been afraid of a curious disease for a long time. The causative agent for the disease had not been identified through the beginning of the 20th century when it turned out that a human parasitic trematode, Schistosoma japonicum, had been afflicting the inhabitants, causing this disease. This was made clear mainly by two medical doctors, Akira Fujinami and Ryuzo Yoshida, much before 1909. The memoir on the disease described by a herb doctor, Yoshinao Fujii (1847), was made known by A. Fujinami to medical scientists in 1909.

Animals↗
PubMed2000

A simplified procedure for purification of cytochrome P-450 by preparative ampholine gel for isoelectric focusing.

The purification process for cytochrome P450 is very complicated, involving five or more column chromatography steps for the final preparation. This paper describes a reduction in the number of the steps; it can be easily purified from pig testis microsomes with improved the yield. As the first step, DEAE-Toyopearl column chromatography is performed only once and then, as the second step, the partially purified cytochrome P450 is completely purified by a preparative Ampholine PAG-plate Gel for Isoelectric Focusing. The combination reduced the purification to a two-step procedure.

Amino Acids↗
PubMed1999

Purification of cytochrome P-450 from adult pig testis by hydroxylapatite and deoxycorticosterone affinity column chromatography.

Adult testicular cytochrome P-450 was purified by a two-step procedure utilizing hydroxylapatite and deoxycorticosterone affinity column chromatography. Cytochrome P-450 was determined to have an isoelectric point of 6.5 on analytical isoelectric focusing. The purified cytochrome P-450 was found to be homogeneous and its molecular mass was estimated to be 52000 on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The carbon monoxide difference spectrum with a peak at 448 nm exhibited the absorption spectrum of a typical cytochrome P-450. A 1000-fold purification was achieved with a yield of 5%.

Animals↗
PubMed1999

A two-step purification of cytochrome P-450 from adult pig testis by pregnenolone affinity column chromatography.

Adult testicular cytochrome P-450 was purified by a two-step procedure utilizing hydroxylapatite and pregnenolone affinity column chromatography. The cytochrome P-450 was determined to have an isoelectric point of 6.43 on analytical isoelectric focusing. The purified cytochrome P-450 was found to be homogeneous and its molecular weight was estimated to be 52,000 on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The carbon monoxide difference spectrum with a peak at 448 nm exhibited the absorption spectrum of a typical cytochrome P-450. A purification of 755x was achieved with a yield of 3.09%.

Ammonium Sulfate↗
PubMed1999

Two-step purification of cytochrome P-450 from adult pig testis by isoelectric focusing.

Adult testicular cytochrome P-450 was purified by a two-step procedure utilizing preparative isoelectrofocusing. Purification was achieved 1132 times with a yield of 4.82%. 17alpha-hydroxylase activity was shown to be 14.5 nmol of product/min/nmol of P-450. The cytochrome P-450 was determined to have an isoelectric point of 6.45 on analytical isoelectric focusing. The purified cytochrome P-450 was found to be homogeneous and its molecular weight was estimated to be 52000 on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The carbon monoxide difference spectrum with a peak at 448 nm exhibited the absorption spectrum of a typical cytochrome P-450.

Animals↗
PubMed1999

Purification of cytochrome P-450 from pig testis by aniline-sepharose 4B and isoelectric focusing.

Testicular cytochrome P-450 was purified by a procedure including preparative isoelectrofocusing. The cytochrome P-450 was determined to have an isoelectric point of 6.47 on analytical isoelectric focusing. The purified cytochrome P-450 was found to be homogeneous and its molecular weight was estimated to be 52,000 on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The carbon monoxide difference spectrum with a peak at 448 nm exhibited absorption spectrum of a typical cytochrome P-450. 284-fold purification was achieved with an yield of 10.6%. Following preparation of the microsomes, the purification is accomplished by a two-step procedure utilizing Aniline-Sepharose 4B column chromatography and preparative isoelectric focusing.

Animals↗
PubMed1998

Purification of cytochrome b5 from pig testis microsomes by isoelectric focusing in an immobiline pH gradient.

Testicular cytochrome b5 was purified by a procedure including preparative isoelectrofocusing. The cytochrome b5 was determined to have an isoelectric point of 4.45 on analytical isoelectric focusing. The purified cytochrome b5 was found to be homogeneous and its molecular weight was estimated to be 16,000 on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The oxidized and reduced forms of the purified preparation exhibited absorption spectra of a typical cytochrome b5. A 69-fold purification was achieved with an overall yield of 6.2%. Following preparation of the microsomes, the purification is accomplished by a two-step procedure utilizing column chromatography and preparative isoelectric focusing.

Acrylamides↗
PubMed1998

Structural analysis of N-linked carbohydrate chains of funnel web spider (Agelenopsis aperta) venom peptide isomerase.

The structure of the N-linked carbohydrate chains of peptide isomerase from the venom of the funnel web spider (Agelenopsis aperta) has been analyzed. Carbohydrates were released from peptide isomerase by hydrazinolysis and reductively aminated with 2-aminopyridine. The fluorescent derivatives were purified by phenol/chloroform extraction, followed by size-exclusion HPLC. The structure of the purified pyridylamino (PA-) carbohydrate chains were analyzed by a combination of two-dimensional HPLC mapping, sugar composition analysis, sequential exoglycosidase digestions, and mass spectrometry. The peptide isomerase contains six kinds of N-linked carbohydrate chains of truncated high-mannose type, with a fucose alpha 1-6 linked to the reducing N-acetylglucosamine in approximately 80% of them.

Amino Acid Isomerases↗
PubMed1998

Role of glutamate receptors and voltage-dependent calcium and sodium channels in the extracellular glutamate/aspartate accumulation and subsequent neuronal injury induced by oxygen/glucose deprivation in cultured hippocampal neurons.

Ischemia is believed to induce neuronal damage by causing a sustained increase in the level of extracellular excitatory amino acids. In our study, we have examined the relationship between oxygen/glucose deprivation-induced changes in extracellular glutamate/aspartate level and subsequent neuronal injury by pharmacological manipulation of glutamate receptors and calcium and sodium channels. Cultured hippocampal neurons were exposed to combined deprivation of oxygen/glucose for 40 to 50 min. These cultures developed acute neuronal swelling and widespread neuronal degeneration over the next 20 hr. The extracellular levels of glutamate and aspartate at the end of the oxygen/glucose deprivation period were measured by high-performance liquid chromatography, and neuronal injury was assessed by lactate dehydrogenase efflux assay after subsequent aerobic incubation of the cells in normal medium for 20 hr. Both N-methyl-D-aspartate and non- N-methyl-D-aspartate receptor antagonists attenuated the extracellular level of glutamate/aspartate and the neuronal injury. L-type, N-type and P-type calcium channel blockers each significantly attenuated the neuronal injury, although the increase in the extracellular glutamate/aspartate was not significantly inhibited by any subtype-specific calcium channel blocker alone. A combination of calcium channel blockers of the three subtypes showed the most prominent neuroprotective effect and inhibited glutamate release. The sodium channel blocker tetrodotoxin also attenuated both glutamate efflux and neuronal injury. These observations suggest that the overactivation of glutamate receptors, calcium channels and sodium channels leads to excitotoxic neuronal injury through enhancing glutamate efflux into the extracellular space under the condition of oxygen/glucose deprivation.

Animals↗
PubMed1996

A factor derived from polymorphonuclear leukocytes enhances interleukin-1-induced synovial cell collagenase and prostaglandin E2 production in rats.

We found that short-term culture medium and homogenate of casein-induced rat peritoneal polymorphonuclear leukocytes (PMN) markedly induced collagenase and prostaglandin E2 (PGE2) production by normal rat synovial cells and these effects were abrogated by anti-(rat interleukin-1 alpha) (IL-1 alpha) polyclonal antibodies. However, collagenase activity and PGE2 induced by recombinant rat IL-1 alpha were less than those induced by rat PMN culture medium. It was also proved by radioimmunoassay that rat PMN culture medium contains a relatively small amount of IL-1 alpha. The introduction of IL-1 alpha-deleted PMN culture medium and recombinant rat IL-1 alpha together into the synovial cell culture system revealed that IL-1 alpha deleted PMN culture medium has a significant enhancing activity on IL-1 alpha-induced synovial cell collagenase and PGE2 production. This new factor, which was shown to be a negatively charged protein of about 80 kDa, may have important roles in connective tissue destruction and chronic inflammation in diseases such as rheumatoid arthritis.

Animals↗
PubMed1996

The relation between two molecular species of P-450 in adult testis and 17 alpha-hydroxylase and 17,20-lyase activities.

Two P-450s from adult pig testis were purified to specific contents of 11.2 and 12.0 nmol P-450/mg protein and shown to have minimum molecular weights of 45,000 and 46,000, respectively. The absorption spectra were typical of P-450s. The P-450s were separated from the two fractions by CM-C50 Sephadex column chromatography. One P-450 (M(r) = 45000) exhibited 17,20-lyase activity of 6.78 nmol of androstenedione/min/nmol P-450, on incubation with 17 alpha-hydroxyprogesterone as a substrate. The other P-450 (M(r) = 46,000) exhibited no 17,20-lyase activity. Both P-450s exhibited 17 alpha-hydroxylase activity that amounted to 10 nmol of steroid products. Accordingly, the two molecular species of P-450 are thus markedly different in 17,20-lyase activity toward 17 alpha-hydroxyprogesterone.

Aldehyde-Lyases↗
PubMed1995

Isolation and characterization of a peptide isomerase from funnel web spider venom.

A novel peptide isomerase was purified from the venom of funnel web spider, Agelenopsis aperta. The complete primary structure of the isomerase has been established by sequence analyses of polypeptide chains, assignments of disulfide bridges, carbohydrate analyses, and mass spectrometry of sugar chains. The isomerase was found to be a 29-kDa polypeptide that consists of an 18-residue light chain and a 243-residue heavy chain connected by a single disulfide bridge. The heavy chain contains three intramolecular disulfide bridges and one N-linked oligosaccharide chain with a simple trimannosyl core structure. A sequence homology search showed a significant similarity of the enzyme with serine proteases, particularly around a putative catalytic triad of the isomerase. The isomerase specifically interconverts the configuration of Ser46 of a 48-amino-acid peptide, omega-agatoxin-TK, and the conversion rate from L-Ser to D-Ser was approximately two times faster than the reverse reaction.

Amino Acid Isomerases↗
PubMed1995

Involvement of P-type calcium channels in high potassium-elicited release of neurotransmitters from rat brain slices.

Several types of voltage-dependent calcium channels appear to occur in neurons, although coupling of the particular subtype of calcium channels to the release of neurotransmitter has not been clearly understood. We have examined the effects of subtype-specific inhibitors of the calcium channels on depolarization-induced release of endogenous neurotransmitters from brain slices. High potassium-induced release of glutamate and aspartate from hippocampal and striatal slices was almost completely inhibited by a P-type channel blocker, omega-agatoxin IVA. omega-Agatoxin IVA also completely inhibited the release of serotonin from the hippocampal slices with almost the same potency as in the case of glutamate, whereas the potency in blocking the release of serotonin and dopamine from striatal slices was lower than that from the hippocampal slices. Another calcium channel blocker, omega-agatoxin TK, that was recently found to block P-type channels with very similar selectivity and potency to omega-agatoxin IVA, also inhibited the release of amino acid transmitters and monoamines, though its potency was lower than that of omega-agatoxin IVA. An N-type channel blocker, omega-conotoxin GVIA, partially inhibited the neurotransmitter release, but an L-type channel blocker, nifedipine was ineffective. We propose that the activation of P-type calcium channels makes a major contribution to depolarization-elicited neurotransmitter release in the CNS and that multiple P-type channels sensitive to omega-agatoxin IVA and omega-agatoxin TK modulate the neurotransmitter release.

Analysis of Variance↗
PubMed1994

Omega-agatoxin-TK containing D-serine at position 46, but not synthetic omega-[L-Ser46]agatoxin-TK, exerts blockade of P-type calcium channels in cerebellar Purkinje neurons.

omega-Agatoxin-TK (omega-Aga-TK), a 48-amino-acid peptide isolated from the venom of the funnel web spider (Agelenopsis aperta), is a selective and potent inhibitor of P-type calcium channels in the nervous system. We have synthesized a peptide that has the amino acid sequence identified for native omega-Aga-TK. The synthetic omega-Aga-TK, however, showed 80-90-fold less potent inhibition of P-type calcium channels, compared with native omega-Aga-TK. Enantiomer analysis of native omega-Aga-TK revealed D-serine at position 46, and synthetic omega-[D-Ser46]Aga-TK had the same potency as native omega-Aga-TK for blocking P-type calcium channels in cultured cerebellar Purkinje neurons. Two peptide fragments of omega-Aga-TK, namely omega-Aga-TK(1-43) and the carboxyl-terminal peptide fragment omega-Aga-TK(44-48), did not produce any significant inhibition of P-type calcium channels or interfere with the blockade of the channels elicited by native omega-Aga-TK. Molecular dynamics calculations showed that the carboxyl-terminal, six-amino-acid peptide of omega-Aga-TK containing D-Ser46 assumes a different conformation than does the peptide containing L-Ser46. These results suggest that the specific conformation of the carboxyl-terminal region of omega-Aga-TK, particularly the configuration of Ser46, together with a beta-sheet structure formed by four disulfide bonds, might be essential for blockade of P-type calcium channels.

Agatoxins↗