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Biomedical subjects

M Kawamura

Publications and source records attributed to M Kawamura.

At least 937 records · Page 52Linked to original sources
PubMed1980

Factors affecting molecular weight conversion of renin.

Our recent findings on molecular weight conversion in the case of renin are summarized and reviewed herein. The molecular weight of renin extracted from isolated renin granules from dogs and rats is approximately 40,000. This renin reacts with a constituent of kidney extract to form a high molecular weight renin of approximately 60,000. This constituent was termed a renin binding substance. This substance is probably contained in the cytosol of kidney cortex, and its characteristics are (1) heat instability, (2) non-dialyzability, (3) loss of binding ability by acidification at pH 3.0 and (4) apparent molecular weight is over 47,000. The binding reaction is mediated in two different ways; thiol oxidation with sodium tetrathionate and exposure of the reaction mixture at 0 degrees C for several days without thiol oxidation.

Animals↗
PubMed1980

A new mass screening method of detecting UDP-galactose-4-epimerase deficiency.

A new mass screening method for detecting UDP-galactose-4-epimerase deficiency in newborn infants was devised so as to make a useful addition to the Guthrie test. Like Beutler's method, this method enables one to perform convenient spot tests on the basis of fluorometry of NADH. The preferred procedure was determined to be as follows: To a mixture of 10 microliter of 5-10 mM UDP-galactose, 10 microliter of 26 mM NAD, 10 microliter of a 1 M tris-HCl buffer (pH 8.0) and 10 microliter of a 1/100 dilution of a 5 mg/ml UDP-glucose dehydrogenase stock solution, distilled water is added until the total volume reaches 100 microliter. Then a blood-bearing filter paper disc is added to the mixture and, the reaction mixture is incubated at 37 degrees C for 6-17 hr. The resulting test solution is spotted on a Whatman No. 1 filter paper with a capillary tube, air-dried and tested for fluorescence with an ultraviolet light detector. No cases of UDP-galactose-4-epimerase deficiency were found in the present study.

Carbohydrate Epimerases↗
PubMed1980

[Laboratory and clinical studies of cefamandole in pediatric infections (author's transl)].

Five patients with suppurative tonsillitis (1), urinary tract infection (1), staphylococcal impetigo (1), cervical lymphadenitis (1) and mycoplasma pneumonia were treated with cefamandole (CMD). CMD was administered by one shot intravenous or drip infusion at a dosage of 100 approximately 135 mg/kg/day for 4 approximately 14 days. Of 5 patients with those infections, excellent response was obtained in 3 patients, good response in 1 patient and unknown response in 1 patient. The overall efficacy rate was 100% except unknown response in mycoplasma pneumonia. In 3 of these 5 cases causative organisms were S. epidermidis, E. coli, and S. aureus, respectively. These organisms were all eliminated. No side effects were observed.

Age Factors↗
PubMed1979

Effect of in vitro aging on 6-ketoprostaglandin F1 alpha-producing activity in cultured human diploid lung fibroblasts.

Prostaglandin synthesis in human diploid fibroblasts was studied by incubating [14C]-arachidonic acid with cell homogenates. The majority of prostaglandins produced in young cells was 6-ketoprostaglandin F1 alpha. The 6-ketoprostaglandin F1 alpha-producing activity of cultures declined with in vitro aging, and was almost undetectable at the senescent stage, while total production of thromboxane B2, prostaglandin F2 alpha and prostaglandin E2-like metabolites increased with in vitro aging.

Cells, Cultured↗
PubMed1979

Characteristics of a renin-binding substance for the conversion of renin into a higher-molecular-weight form in the dog.

1. Renal cortical homogenates of the dog were subjected to sieve separation, a Nucleopore Filter being used to separate the renin granules. 2. The molecular weight of renin in the granules was estimated to be about 40 000 by gel filtration. Renin was converted into a higher-molecular-weight form (60 000) by mixing with cytosol in the presence of sodium tetrathionate, a thiol inhibitor. 3. When cytosol was pretreated with acid (pH 3.0) or heating (100 degrees C), the molecular-weight conversion did not occur. 4. Cytosol was separated into three parts by gel filtration. Fraction A included substances with a molecular weight of over 47 000, fraction B from 47 000 to 32 000, and fraction C from 32 000 to 15 000. The mixture of renin in the granules with fraction A and sodium tetrathionate resulted in the formation of a higher-molecular-weight form of the enzyme, but no change in molecular weight was detected when renin was mixed with fractions B or C and sodium tetrathionate.

Animals↗
PubMed1979

Relationship between molecular weight conversion and renin activity in dog renal renin.

A normal size form of renin, which seems to be a storage form in renin granules, changed neither in molecular weight nor activity by acidification to pH 3.0. High molecular weight (HMW) renin fractionated by gel chromatography from crude renal extract prepared with thiol group blockers was converted into normal size renin by acdification, accompanied with an increase in renin activity by about 50%. The molecular weight conversion by acidification appeared due to destruction or loss of binding ability of the renin binding substance which was present in the cytosol of renal cortical tissue. Renin and renin binding substance could combine into HMW renin at neutral pH in the presence of thiol group blockers and renin activity decreased.

Acids↗
PubMed1978

Anthranilate synthetase component II from Pseudomonas putida. Covalent structure and identification of the cysteine residue involved in catalysis.

The complete amino acid sequence of carboxamidomethylated anthranilate synthetase component II (AS II) from Pseudomonas putida has been determined by analysis of cyanogen bromide fragments, tryptic peptides from the citraconylated protein, and by analysis of subdigests of these peptides. AS II is a single polypeptide chain of 197 residues having a calculated molecular weight of 21,684. Previous studies (Goto, Y., Keim, P. S., Zalkin, H., and Heinrikson, R. L. (1976) J. Biol. Chem, 251, 941-949) identified a cysteine residue required for the formation of an acyl-enzyme intermediate. The protein has 3 cysteine residues at positions 54, 79, and 140. Cysteine-79 was alkylated selectively by iodoacetamide and by the glutamine affinity analogue L-2-amino-4-oxo-5-chloropentanoic acid. Based on this evidence cysteine-79 is the active site residue involved in formation of the acyl-enzyme intermediate. Comparison of the P. putida AS II sequence with that of the NH2-terminal 60 residues of the enzyme from Escherichia coli shows 38% sequence identity.

Amino Acid Sequence↗