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Biomedical subjects

T Beppu

Publications and source records attributed to T Beppu.

At least 343 records · Page 19Linked to original sources
PubMed1982

Serum bile acid profiles in cerebrotendinous xanthomatosis.

Non-sulfated bile acid concentrations in sera of 10 cases of cerebrotendinous xanthomatosis (CTX) were determined by mass fragmentography. Total bile acid (TBA) in serum was 0.492 +/- 0.436 microgram/ml (mean +/- SD) which was significantly lower than that (1.481 +/- 0.571) in healthy control sera. Cholic acid was 0.342 +/- 0.291 microgram/ml and was the dominant bile acid, which constituted 69.5% of TBA in serum. Chenodeoxycholic acid was 0.111 +/- 0.133 microgram/ml being a minor component in CTX sera, although it was the major bile acid in healthy control sera. Other bile acids such as deoxycholic acid, lithocholic acid and ursodeoxycholic acid were scarcely detected. Subnormal TBA level and deranged bile acid composition in CTX sera may reflect the defect of bile acid biosynthesis in CTX patients. Determination of serum bile acid may be useful in the diagnosis of CTX.

Adult↗
PubMed1982

Expression of cloned calf prochymosin gene sequence in Escherichia coli.

An expression plasmid for calf prochymosin (prorennin) cDNA was constructed. The plasmid (pCR301) contains the lacUV5 promoter in front of the fused gene in which the codons for the N-terminal four amino acids of prochymosin cDNA were replaced with those for the N-terminal ten amino acids of beta-galactosidase. Synthesis of the fused protein with the expected Mr was detected immunologically in Escherichia coli harboring pCR301. The product seemed to be localized in the cell membrane of the bacterial host.

Amino Acid Sequence↗
PubMed1982

Nucleotide sequence of calf prorennin cDNA cloned in Escherichia coli.

The nucleotide sequence of prorennin (prochymosin) cDNA cloned in E. coli was determined by the technique of Maxam and Gilbert. The longest prorennin cDNA insert in pTACR1 contained the putative signal sequence and the coding sequence for the peptide from the 1st amino acid, Ala (NH2 terminal), to the 296th, Ser, and the other clone pTACR9 contained the coding sequence from the 258th, Asp, to the 365th, Ile (COOH terminal), and the TGA termination codon followed by the 3'-untranslated region. Thus, the whole coding sequence for prorennin was obtained in the pair of pTACR1 and pTACR9.

Amino Acid Sequence↗
PubMed1982

Photo-oxidation of a histidyl residue of milk-clotting acid protease, Mucor rennin.

Mucor rennin, a milk-clotting acid protease produced by a fungus Mucor pusillus, was inactivated by photo-oxidation mediated by methylene blue according to first order kinetics. The pH profile of the inactivation rate showed that a dissociating group with a pK value of 7.6 was involved in the inactivation. Addition of pepstatin A, an inhibitor specific for acid proteases, caused a marked alkaline shift of the pK value. One of two histidyl residues in the enzyme was destroyed by the photo-oxidation, with complete loss of the enzyme activity. Analysis of inhibitor binding activity and chemical modification with diazoacetyl-DL-norleucine suggested that the photo-oxidized enzyme still retained its original conformation. These results indicated that one histidyl residue in addition to the two essential carboxyl groups is involved in the catalytic function of Mucor rennin.

Chymosin↗
PubMed1982

Proton magnetic resonance spectroscopy of an essential histidyl residue in a milk-clotting acid protease, Mucor rennin.

The location and state of an essential histidyl residue in a milk-clotting acid proteases, Mucor rennin, were investigated by NMR spectroscopy. Assignment of the C2H resonance peak of the essential histidyl residue was possible by comparison of the NMR spectrum of the native enzyme with that of the photo-oxidized enzyme. The pH titration curve for the chemical shift of the C2H proton showed two inflections, a major one with pKa = 7.4 and a minor one with pKa = 3.5 at 30 degrees C. The major inflection, corresponding to an intrinsic protonation of the imidazole ring, shifted toward the alkaline side upon addition of acetyl pepstatin, an inhibitor specific for the acid protease. Modification of an essential carboxyl group in the enzyme with diazoacetyl-DL-norleucine caused disappearance of the minor inflection as well as an acidic shift of the major pKa value. Perturbation effects on the C2H resonance of the lanthanide metals, Pr3+, Eu3+, and Gd3+, suggested their selective binding to a carboxyl group and location of the bound metal atom close to the essential histidyl residue. All data suggested that the essential histidyl residue of Mucor rennin is located close to one of the two essential carboxyl groups in the catalytic site of the enzyme.

Animals↗
PubMed1982

Quantitative determination of bile acid glucuronides in serum by mass fragmentography.

Individual non-glucuronidated . non-sulfated, glucuronidated and sulfated bile acids in serum were determined, i.e. lithocholic acid, deoxycholic acid, chenodeoxycholic acid, ursodeoxycholic acid, and cholic acid, by mass fragmentography. Glucuronic acid conjugates of lithocholic acid, deoxycholic acid, chenodeoxycholic acid, and cholic acid were synthesized via the Koenigs-Knorr condensation reaction. Deuterium labeled deoxycholic acid, lithocholic acid glucuronide, deoxycholic acid glucuronide, and deoxycholic acid sulfate were synthesized and used as internal standards. A serum sample of 1 ml including internal standards was purified with a Sep-Pak C18 cartridge. After the enzymatic cleavage of amino acid conjugates, bile acids were separated into three fractions, free, glucuronidated, and sulfated bile acids, using piperidinohydroxypropyl Sephadex LH-20 (Goto et al. (1978) Clin. Chim. Acta 87). Glucuronidated and sulfated bile acids were deconjugated by beta-glucuronidase treatment and solvolysis. Each fraction was converted to the hexafluoroisopropyl-trifluoroacetyl derivative and quantitated by mass fragmentography. The average concentrations of individual bile acid glucuronides from healthy fasting subjects (n = 9) were as follows; lithocholic acid 0.013 microgram/ml, deoxycholic acid 0.083 microgram/ml, chenodeoxycholic acid 0.078 microgram/ml, ursodeoxycholic acid 0.013 microgram/ml, and cholic acid 0.007 microgram/ml. Bile acid glucuronides occupied 7.8% of the total bile acids.

Bile Acids and Salts↗
PubMed1982

A case of cerebrotendinous xanthomatosis: effects of ursodeoxycholic acid administration on serum bile acids and cholestanol.

Cerebrotendinous xanthomatosis (CTX) is a rare familiar disease characterized by tendon xanthomas, cataracts, cerebellar ataxia, dementia and an elevated serum cholestanol level. In this paper, a 50-year-old man with typical signs and symptoms of CTX is described. Serum cholestanol and chelesterol concentrations were 17.9-28.6 micrograms/ml and 109-153 mg/dl, respectively. The determination of non-sulfated bile acid concentration in the serum assayed by mass fragmentography disclosed an abnormal profile. The concentration of cholic acid (0.30-0.52 microgram/ml) was higher than normal, while those of chenodeoxycholic acid, ursodeoxycholic acid, deoxycholic acid and lithocholic acid were extremely low or undetectable. Administration of ursodeoxycholic acid (300 mg per day, orally) for 2 weeks resulted in a marked reduction of serum cholic acid concentration. However, serum cholestanol levels remained unchanged.

Bile Acids and Salts↗
PubMed1982

Induction of streptomycin-inactivating enzyme by A-factor in Streptomyces griseus.

The effect of A-factor on streptomycin resistance and productivity in Streptomyces griseus and S. bikiniensis was studied using A-factor-negative mutants. Resistance of several of these mutants was markedly increased by adding A-factor to the growing medium, as also was their streptomycin productivity. The A-factor induced resistance was due to inactivation by streptomycin-6-phosphotransferase, and enzyme synthesis in these mutants was completely dependent on the presence of A-factor. In the case of S. griseus 2247 where streptomycin productivity was independent of A-factor, resistance and synthesis of the inactivating enzyme were also independent of A-factor. A-Factor-negative mutants of S. griseus showed a decreased level of NADP-glycohydrolase and an increased level of several NADP-linked dehydrogenases, but these enzymes did not return to parental levels in cultures supplemented with A-factor. A-Factor seems to regulate streptomycin biosynthesis, not through an indirect metabolic sequence involving these enzymes but, more likely, by directly stimulating synthesis of enzyme(s) in the biosynthetic pathway.

4-Butyrolactone↗
PubMed1982

Mutants blocked in streptomycin production in Streptomyces griseus - the role of A-factor.

Ninety-five streptomycin-nonproducing mutants derived from Streptomyces griseus FT-1 by UV-irradiation could be classified into major two classes by cosynthesis tests. Class I mutants (42 strains) were mutants blocked in the pathway of streptomycin biosynthesis while class II mutants (49 strains) required a factor for streptomycin biosynthesis which was excreted by the parental or class I mutant strains. The factor could be replaced by synthetic A-factor (2S-isocapryloyl-3-S-hydroxymethyl-gamma-butyrolactone) which restored both streptomycin biosynthesis and spore formation in the class II mutants. A-Factor deficient mutants were obtained from several strains of S. griseus and S. bikiniensis at high frequency by treatment with acridine orange or incubation at high temperature. A mutant whose streptomycin biosynthesis was independent of A-factor deficiency was found. The production of A-factor was distributed among various species of actinomycetes.

4-Butyrolactone↗
PubMed1981

Treatment of intrahepatic lithiasis using the choledochofiberscope.

Our experience with choledochoscopic extraction of intrahepatic calculi in eleven cases is presented. In three cases, the intrahepatic bile duct containing multiple stones was punctured under the guidance of ultrasonography, and the stones were removed choledochoscopically through the percutaneous transhepatic cholangial drainage (PTCD) tract which was dilated with catheters of increasing diameter. In nine cases, the removal of intrahepatic stones was attempted choledochoscopically through the T-tube tract or the jejunostomy. This procedure was successful in six of the nine cases. The advantage of the choledochoscopic removal through the PTCD tract compared with that through the T-tube tract is discussed, and an illustrative case is presented.

Adult↗
PubMed1981

Purification and properties of a copper-containing nitrite reductase from a denitrifying bacterium, Alcaligenes faecalis strain S-6.

A copper-containing nitrite reductase was purified and crystallized from a potent denitrifying bacterium, Alcaligenes faecalis strain S-6. The enzyme was composed of 4 subunits with a molecular weight of about 30,000, each containing 1 atom of Cu2+. Nitric oxide was identified as a main reduction product from nitrite in the enzyme-catalyzed reaction. The enzyme activity was inhibited strongly by KCN but only slightly by sulfhydryl reagents such as p-chloromercuribenzoate and N-ethylmaleimide.

Alcaligenes↗
PubMed1981

A blue protein as an inactivating factor for nitrite reductase from Alcaligenes faecalis strain S-6.

A blue protein with a molecule weight of 12,000 containing 1 atom of type I Cu2+ was purified and crystallized from a denitrifying bacterium, Alcaligenes faecalis strain S-6, as an inactivating factor for copper-containing nitrite reductase of the same organism. Inactivation of the enzyme occurred when the enzyme was incubated aerobically with a catalytic amount of the blue protein in the presence of reducing agents such as cysteine and ascorbate. The blue protein acts as a direct electron donor for the enzyme to catalyze the reduction of nitrite, but in the absence of nitrite, the enzyme-reduced blue protein system reacts with oxygen to produce H2O2. A suicide inactivation mechanism of the enzyme due to this H2O2 production is proposed.

Alcaligenes↗