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T Suga

Publications and source records attributed to T Suga.

At least 217 records · Page 12Linked to original sources
PubMed1988

Amino acid sequences of two nonspecific lipid-transfer proteins from germinated castor bean.

The amino acid sequence of two nonspecific lipid-transfer proteins (nsLTP) B and C from germinated castor bean seeds have been determined. Both the proteins consist of 92 residues, as for nsLTP previously reported, and their calculated Mr values are 9847 and 9593 for nsLTP-B and nsLTP-C, respectively. The sequences of nsLTP-B and nsLTP-C, compared to the known sequence of nsLTP-A from the same source, are 68% and 35% similar, respectively. No variation was found at the positions of the cysteine residues, indicating that they might be involved in disulfide bridges.

Amino Acid Sequence↗
PubMed1988

The structure of jack bean urease. The complete amino acid sequence, limited proteolysis and reactive cysteine residues.

The amino acid sequence of jack bean urease has been determined. The protein consists of a single kind of polypeptide chain containing 840 amino acid residues. The subunit relative molecular mass calculated from the sequence is 90,770, indicating that urease is composed of six subunits. Out of 25 histidine residues in urease, 13 were crowded in the region between residues 479 and 607, suggesting that this region may contain the nickel-binding site. Limited tryptic digestion cleaved urease at two sites, Lys-128 and Lys-662. Proteolytic products were not dissociated and retained full enzymatic activity. Five tryptic peptides containing the reactive cysteine residues were isolated and characterized with the aid of sulfhydryl-specific reagents, N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine and N-(7-dimethylamino-4-methyl-3-coumarinyl)-maleimide. The reactive cysteine residues were located at positions 59, 207, 592, 663, and 824. The possibility that Cys-59, Cys-207, Cys-663, and Cys-824 are involved in the urease activity of the enzyme has been eliminated. Cys-592, which is essential for enzymatic activity, is located in the above-mentioned histidine-rich region.

Amino Acid Sequence↗
PubMed1988

Suppression of clofibrate-induced peroxisome proliferation in rat liver by nicardipine, a calcium antagonist.

In vivo administration of nicardipine, nifedipine and diltiazem, known as calcium antagonists, suppressed the clofibrate-evoked induction of activities of peroxisomal enzymes, such as the peroxisomal fatty acyl-CoA oxidizing system and carnitine acetyltransferase. The inhibition activity of nicardipine with respect to clofibrate induction of the two enzyme systems was 62 and 33%, respectively. Induction of the peroxisomal bifunctional protein, enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase, by clofibrate was suppressed about 60% by nicardipine on analysis of the hepatic protein composition by SDS-polyacrylamide gel electrophoresis. Other drugs also exhibited similar inhibitory activity. These results provide the first demonstration of calcium antagonists, e.g. nicardipine, nifedipine and diltiazem, acting as inhibitors of peroxisome proliferation in animals. Such drugs might become useful as tools for elucidating the mechanism of peroxisome proliferation and for determination of the pathological conditions under which peroxisomal function is impaired.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1988

Influence of 5-tridecylpyrazole-3-carboxylic acid, a new hypolipidaemic agent, on cholesteryl ester formation in rabbit intestinal mucosa.

The comparative effects of 5-tridecylpyrazole-3-carboxylic acid (TDPC), beta-sitosterol and melinamide on the esterification of cholesterol (CH) have been investigated in rabbit intestinal microsomes and cytosol in-vitro. The three agents did not show an effect on cholesteryl ester formation by cholesterol esterase (CEase). TDPC and beta-sitosterol did not affect cholesteryl oleate formation from oleoyl CoA by microsomal acyl CoA:cholesterol acyltransferase (ACAT), whereas melinamide significantly inhibited cholesteryl oleate formation. TDPC significantly inhibited the incorporation of oleic acid into cholesteryl oleate, which is associated with acyl CoA synthetase (ACS) plus ACAT in mucosal microsomes, at a concentration of 20-100 microM. On the other hand, 5-tridecylpyrazole-3-carbinol (TDPC-OH) a congener of TDPC, and beta-sitosterol did not show any effect. From these results, it is demonstrated that carboxylic moiety of TDPC is necessary to inhibit ACS in-vitro. According to the kinetic analytical results, it is suggested that TDPC acts as a competitive inhibitor of ACS. These results suggest that the inhibitory effect of TDPC on cholesteryl ester formation may be mediated by an inhibition of ACS activity. It is apparent from the data presented that there are substantial differences between TDPC, beta-sitosterol and melinamide with respect to their action on cholesteryl ester formation in rabbit intestinal mucosa.

Animals↗
PubMed1988

Levels of circulating IgA immune complexes after gluten-rich diet in patients with IgA nephropathy.

Measurement of IgA circulating immune complexes (IgA-CIC) in sera from patients with IgA nephropathy after a gluten-poor diet, an unrestricted diet and a gluten-rich diet is described. High levels of IgA-CIC in sera were detected in patients after these diets. However, the levels of IgA-CIC in sera 2 weeks after the gluten-rich diet were not significantly increased compared with those after the other diets. It is suggested that, for a short duration, the gluten-rich diet might not increase the levels of IgA-CIC in sera from Japanese patients with IgA nephropathy.

Adolescent↗
PubMed1988

Characterization of argentosomes, a type of secondary lysosomes, and the sub-organellar distribution of a lysosomotropic basic compound.

Secondary lysosomes (argentosomes) were isolated by centrifugation in a discontinuous sucrose density gradient from livers of rats administered colloidal silver. Compared to the crude homogenate, the purities of the argentosome preparations were 17.4- and 18.5-fold in terms of acid phosphatase and N-acetyl-beta-glucosaminidase activities, respectively. By lipid analysis, the argentosomes were shown to have intermediate properties between normal lysosomes and tritosomes with regard to the contents of triglyceride and cholesterol. The phospholipid content in the argentosomes was also different from that in these two organelles. The cross-point of argentosomes shifted more to the acidic side than that of normal lysosomes. The data on the binding of tritiated p- biphenylmethyl-(dl-tropyl-alpha-tropiniun)bromide [( 3H]BTTB) to argentosomes indicated that the degree of binding and/or incorporation of this basic compound to the organelles was much higher than that to normal lysosomes. These results suggested that the distribution of BTTB on or within argentosomes might be under the control of the surface charge of the argentosomal membranes.

Animals↗
PubMed1988

Induction of peroxisome proliferation in rat liver by dietary treatment with 2,2,4,4,6,8,8-heptamethylnonane.

1. Exposure of rats to 1% (w/w) of 2,2,4,4,6,8,8-heptamethylnonane in the diet for 2 weeks resulted in marked induction of liver peroxisome proliferation as judged from electron micrography, elevated activities of hepatic catalase (36%), cyanide-insensitive palmitoyl-CoA oxidase (10-fold), carnitine acetyl transferase (9.6-fold), lauric acid hydroxylase (12.4-fold), and the induction of the 80 K protein in SDS-polyacrylamide gel electrophoresis (4.1-fold). 2. 2,2,4,4,6,8,8-Heptamethylnonane dicarboxylic acid, a non-beta-oxidizable fatty acid, was detected as the major metabolite in the liver, an example of an unmetabolizable lipophilic anion as a peroxisome proliferator.

Alkanes↗
PubMed1988

Carbazomycins G and H, novel carbazomycin-congeners containing a quinol moiety.

Carbazomycins G (I) and H (II), new congeners of the carbazomycin complex, have been isolated from the culture broth of Streptoverticillium ehimense. They have proved to contain a unique quinol moiety in the molecule. Their structures have been elucidated by mass and NMR spectrometries and X-ray crystallographic analysis. Carbazomycin G showed moderate antifungal activity against Trichophyton species.

Anti-Bacterial Agents↗
PubMed1988

[Detachable balloon treatment of vertebral fusiform aneurysms].

Percutaneous embolization using a detachable balloon in six cases of vertebral fusiform aneurysm is reported. Location of these aneurysms were as follows; 5 aneurysms in the distal vertebral artery (2 proximal to the posterior inferior cerebellar artery; PICA, 2 distal to the PICA and 1 where the PICA was undetectable), and one aneurysm in the extracranial vertebral artery. Three cases suffered from subarachnoid hemorrhage (dissecting aneurysms) and other cases showed lower cranial nerve palsy (giant aneurysm) or posterior fossa ischemia. Most of the cases were treated immediately after conventional diagnostic angiography, especially those cases with subarachnoid hemorrhage (within 4 days after the last attack). Under local anesthesia, a catheter was positioned in the affected vertebral artery either trans-femorally or trans-axillary. The detachable balloon was placed proximal to the aneurysm and test occlusion was performed for 15-20 minutes (the tolerance test or balloon Matas' test). After it was confirmed that there had been no neurological deterioration, the vertebral artery was permanently occluded by detachment of the balloon. The procedure was successful in all cases. Thrombosis of aneurysms was confirmed either by follow-up angiography or by autopsy. However, two cases who were grade V (Hunt & Kosnik) at admission died of severe vasospasm. PICA was preserved through either ipsilateral or contralateral collaterals. Detachable balloon occlusion of the vertebral artery for fusiform aneurysm is thought to be less invasive, more indicative and a safer procedure compared to conventional surgical proximal occlusion therapy.

Adult↗
PubMed1988

Polyclonal IgA in IgA nephropathy.

Polyclonality of IgA production in IgA nephropathy (IgAN) was studied to elucidate the immunological aberrations in patients with this disease. The amounts of IgG, IgA and IgM and their kappa/lambda ratios in sera and supernatants of lymphocyte cultures were determined by the enzyme-linked immunosorbent assay. This method was sensitive enough to detect as little as 10% of monoclonal IgA in total IgA. The amount of IgA in IgAN was significantly increased in sera and supernatants without pokeweed-mitogen (PWM), but not changed in supernatants with PWM. There were no significant changes in the production of other immunoglobulins between IgAN and controls both in vivo and in vitro with and without addition of PWM. As far as the kappa/lambda ratios of immunoglobulins were concerned, no significant deviations were observed between IgAN and controls in any samples. These results indicated that increased IgA in patients with IgAN was polyclonal, supporting the concept of the heterogeneity of this disorder.

Adolescent↗
PubMed1987

Participation of peroxisomes in the metabolism of xenobiotic acyl compounds: comparison between peroxisomal and mitochondrial beta-oxidation of omega-phenyl fatty acids in rat liver.

The peroxisomal beta-oxidation of omega-phenyl fatty acids (PFAs) as model compounds for xenobiotic acyl compounds was investigated. In isolated hepatocytes, omega-phenyllauric acid (PFA12) was chain-shortened to PFAs having an even number of carbon atoms in the acyl side chain. Associated with this reaction, H2O2 generation was observed, the rate of which was markedly enhanced by clofibrate treatment of rats. Also when using isolated peroxisomes, such a chain-shortening of PFA12 occurred, associated with stoichiometrical production of NADH and acetyl-CoA. The CoA-ester form of PFA12 as a substrate and NAD as a cofactor were required in this reaction, indicating the participation of peroxisomal beta-oxidation in the chain-shortening of PFA12. When using PFAs with various chain lengths, the rates of H2O2 generation measured as the peroxisomal beta-oxidation in isolated hepatocytes were similar to those with the corresponding fatty acids, whereas the rates of ketone body production measured as the mitochondrial beta-oxidation were much lower than that with any fatty acid examined. From the study with isolated mitochondria and purified enzymes, it was found that the mitochondrial beta-oxidation of PFAs was carnitine-dependent, and that the activities of carnitine palmitoyltransferase for PFA-CoAs are low. Moreover, the activities of acyl-CoA dehydrogenase for PFA-CoAs were lower than those for fatty acyl-CoAs, while the activities of acyl-CoA oxidase for PFA-CoAs were comparable to those for fatty acyl-CoAs. As a result, relatively long chain PFAs were hardly subjected to mitochondrial beta-oxidation. Based on the maximum enzyme activities of the beta-oxidation, which were measured by following acyl-CoA-dependent NAD reduction in isolated peroxisomes and O2 consumption in isolated mitochondria, about 60% of the beta-oxidation of PFA12 in the rat liver was peroxisomal. In clofibrate-treated rats, the value reached about 85%. From these results it is concluded that the peroxisome is one of the important sites of degradation of xenobiotic acyl compounds.

Acetyl Coenzyme A↗
PubMed1987

Purification and properties of peroxisomal carnitine palmitoyltransferase in chick embryo liver.

Peroxisomal carnitine palmitoyltransferase was purified by solubilization using Tween 20 and KCl from the large granule fraction of the liver of clofibrate-treated chick embryo, DEAE-Sephacel and blue Sepharose CL-6B column chromatography. The peroxisomal carnitine palmitoyltransferase was an Mr 64,000 polypeptide; the mitochondrial carnitine palmitoyltransferase had a subunit molecular weight of 69,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The carnitine acetyltransferase was an Mr 64,000 polypeptide. Antibody against purified peroxisomal carnitine palmitoyltransferase reacted only with peroxisomal carnitine palmitoyltransferase, but not with mitochondrial carnitine palmitoyltransferase or carnitine acetyltransferase. In addition, anti-peroxisomal carnitine palmitoyltransferase reacted only with the protein in peroxisomes purified from chick embryo liver by sucrose density gradient centrifugation. Thus, it was confirmed that purified peroxisomal carnitine palmitoyltransferase was a peroxisomal protein. Compared with mitochondrial carnitine palmitoyltransferase, peroxisomal carnitine palmitoyltransferase was extremely resistant to inactivation by trypsin. The pH optimum of peroxisomal carnitine palmitoyltransferase was 8.5, differing from that of mitochondrial carnitine palmitoyltransferase. The Km value of peroxisomal carnitine palmitoyltransferase for palmitoyl-CoA (32 microM) was similar to that of the mitochondrial one, whereas those values for L-carnitine (140 microM), palmitoyl-L-carnitine (43 microM) and CoA (9 microM) were lower than those of mitochondrial carnitine palmitoyltransferase. Peroxisomal carnitine palmitoyltransferase exhibited similar substrate specificities in both the forward and reverse reactions, with the highest activity toward lauroyl derivatives. Furthermore, this enzyme showed relatively high affinities for long-chain acyl derivatives (C10-C16) and similar Km values (30-50 microM) for acyl-CoAs, acylcarnitine and CoA, and a constant Km value (approximately 150 microM) for carnitine. These results indicate that peroxisomal carnitine palmitoyltransferase played a role in the modulation of the intracellular CoA/long-chain acyl-CoA ratio at the hatching stage of chicken when long-chain fatty acids are actively oxidized in peroxisomes.

Acyltransferases↗
PubMed1987

Effects of various basic compounds on the degradation of formaldehyde-treated 125I-labeled bovine serum albumin in mouse liver lysosomes.

The effect of various basic compounds on degradation of formaldehyde-treated 125I-bovine serum albumin (denatured 125I-BSA) in livers of mice was studied in detail. Five basic compounds (BTTB, chloroquine, methylamine, ammonium chloride, and vinblastine) were tested. All the basic compounds inhibited the degradation of exogenous protein in lysosomes. When p-biphenylmethyl-(dl-tropyl-alpha-tropinium)bromide (BTTB) was used, the most effective inhibition was obtained at the concentration of 3.2 mM. Also, vinblastine, a well-known inhibitor of microtubular function, inhibited the degradation of an exogenous protein to the similar extent as that of chloroquine. The inhibition of protein degradation caused by BTTB closely related to the uptake of BTTB into lysosomes. It is supposed that BTTB accumulates in lysosomes and that it inhibits the hydrolytic enzyme by neutralizing intralysosomal pH. Furthermore, it is supposed that BTTB, a quaternary ammonium compound, becomes a useful tool in the study of protein degradation in lysosomes as well as the typically lysosomotropic compounds (chloroquine, ammonium chloride, and methylamine).

Acid Phosphatase↗
PubMed1987

Existence of fatty acyl-CoA oxidizing system in (micro)peroxisomes of rabbit aorta.

A cyanide-insensitive palmitoyl-CoA oxidizing activity was detected in rabbit aorta. An assay developed for the arterial acyl-CoA oxidizing system was linear with respect to protein content of the homogenate between 12.5 and 100 micrograms and incubation time for at least 15 min. The system was shown to be localized in (micro)peroxisomes by centrifugation in sucrose density gradient. With a diet containing 1% (w/w) cholesterol and 3% (w/w) olive oil for 8 weeks the activity of peroxisomal beta-oxidation increased from 1.38 to 2.54 nmole/min/g aorta. These results show that the aortic catalase-positive particles have a capacity to oxidize fatty acyl-CoA and participate in fatty acid metabolism.

Acyl Coenzyme A↗
PubMed1987

Influence of the new antihypertensive drug, SM-2470 (a quinazoline derivative), on cholesterol metabolism in rats.

The influence of SM-2470 (4-amino-2-(4-[bicyclo(2,2,2)oct-2-ene-5-carbonyl]-1-piperazinyl)- 6,7-dimethoxyquinazoline), a new antihypertensive agent, on cholesterol metabolism was investigated in hypercholesterolaemic rats, using the dual isotope method (cholesterol absorption) and the intestinal ligated loop method (cholesterol uptake). In the hypercholesterolaemic model, 1-30 mg kg-1 doses of SM-2470 significantly inhibited the elevation of the total serum cholesterol and very low and low density lipoproteins (VLDL + LDL)-cholesterol, without causing any change in the hepatic cholesterol level. In a dual isotope model experiment, SM-2470 (10, 30 mg kg-1) inhibited the intestinal absorption of cholesterol, but did not affect biliary excretion of sterol and/or bile acids, nor did it affect cholesterol movement from the liver to blood. In the intestinal ligated loop method, SM-2470 remarkably inhibited the mucosal uptake of cholesterol in a dose-dependent manner in 0.5-2.0 mg mL-1 of micellar solution. In addition, SM-2470 inhibited micellar formation in-vitro, which increased the distribution of large sized micelles as well as cholesterol absorption inhibitors. From these results, it can be assumed that a possible mechanism behind the hypocholesterolaemic effect of SM-2470 is the inhibition of cholesterol absorption related to the reduction of cholesterol solubilization, occurring in the gut micelles, similar to the action of plant sterol.

Adrenergic alpha-Antagonists↗
PubMed1987

Modified open renal biopsy: results in 934 patients.

Nine hundred and thirty-four cases of open renal biopsy using the 'Kawamura-modified forceps' have been performed over the past 9 years under general anesthesia. Sufficient amounts of renal tissue for routine histology, immunofluorescence staining and electron microscopy were obtained in all 934 cases. There were no serious major complications attributable to the procedure. It is concluded that this procedure can be performed easier and faster than the previous technique of percutaneous renal biopsy, although patients undergoing open renal biopsy with the Kawamura-modified forceps have to be transferred to the operating room for this procedure.

Adolescent↗