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Biomedical subjects

S Kawabata

Publications and source records attributed to S Kawabata.

At least 253 records · Page 14Linked to original sources
PubMed1985

The complete amino acid sequence of coagulogen isolated from Southeast Asian horseshoe crab, Carcinoscorpius rotundicauda.

The complete amino acid sequence of coagulogen purified from the hemocytes of the horseshoe crab Carcinoscorpius rotundicauda was determined by characterization of the NH2-terminal sequence and the peptides generated after digestion of the protein with lysyl endopeptidase, Staphylococcal aureus protease V8 and trypsin. Upon sequencing the peptides by the automated Edman method, the following sequence was obtained: A D T N A P L C L C D E P G I L G R N Q L V T P E V K E K I E K A V E A V A E E S G V S G R G F S L F S H H P V F R E C G K Y E C R T V R P E H T R C Y N F P P F V H F T S E C P V S T R D C E P V F G Y T V A G E F R V I V Q A P R A G F R Q C V W Q H K C R Y G S N N C G F S G R C T Q Q R S V V R L V T Y N L E K D G F L C E S F R T C C G C P C R N Y Carcinoscorpius coagulogen consists of a single polypeptide chain with a total of 175 amino acid residues and a calculated molecular weight of 19,675. The secondary structure calculated by the method of Chou and Fasman reveals the presence of an alpha-helix region in the peptide C segment (residue Nos. 19 to 46), which is released during the proteolytic conversion of coagulogen to coagulin gel. The beta-sheet structure and the 16 half-cystines found in the molecule appear to yield a compact protein stable to acid and heat. The amino acid sequences of coagulogen of four species of limulus have been compared and the interspecies evolutionary differences are discussed.

Amino Acid Sequence↗
PubMed1985

Enzymatic properties of staphylothrombin, an active molecular complex formed between staphylocoagulase and human prothrombin.

Staphylocoagulase with a molecular weight of 64,000 and subspecies ranging in molecular weight from 36,000 to 64,000 were purified by affinity column chromatography on bovine prothrombin-Sepharose 4B from the culture filtrates of the Staphylococcus aureus strains, st-213 and 104. The samples containing all molecular species from both strains had the same NH2-terminal sequence, Ile-Val-Thr-Lys-Asp-Tyr-Ser-Lys-Glu-, implying that the molecular heterogeneity was due to proteolytic degradation to some extent of the COOH-terminal portion during cultivation or purification. Staphylocoagulase (Mr = 64,000) from strain st-213 formed an active complex, "staphylothrombin," with human prothrombin in a molar ratio of 1 to 1.1. Staphylothrombin was unstable at 37 degrees C and some portions of staphylocoagulase in the complex were rapidly degraded into small fragments, together with the fragmentation of prothrombin into prethrombin 1 and prothrombin fragment 1. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subsequent fluorography for the products of prothrombin activation by staphylocoagulase in the presence of [3H]diisopropylphosphofluoridate (DFP) demonstrated the formation of a DFP-sensitive active site in the prothrombin molecule, and no cleavage of the Arg-Ile bond linking the A and B chains of alpha-thrombin was found. The enzymatic properties including the pH-dependency of the activity, substrate specificity and behavior towards thrombin inhibitors of staphylothrombin differed from those of alpha-thrombin, although the active site titration of staphylothrombin with p-nitrophenyl-p'-guanidinobenzoate showed 0.95 +/- 0.2 mol of active site/mol of enzyme.

Amidohydrolases↗
PubMed1984

Purification and characterization of Staphylococcus aureus FRI 1169 and 587 toxic shock syndrome exotoxins.

An exotoxin was purified from a toxic shock toxin (TST)-producing Staphylococcus aureus strain, FRI 1169, and another exotoxin was purified from a pyrogenic exotoxin C (PEC)-producing S. aureus strain, 587. Both strains had been isolated from toxic-shock syndrome patients. The two exotoxins were purified by the same method of ion-exchange chromatography, chromatofocusing, and gel filtration. After purification, those exotoxins gave a line of identity against an anti-TST serum and also were immunologically similar to TST in a double-diffusion test. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, each exotoxin gave a single band with a relative mobility identical to that of the other. Their molecular weights (24,000), isoelectric points (7.0), amino acid compositions, and NH2-terminal amino acid sequences (the first four residues) were identical. Both produced fever and enhanced host susceptibility to lethal endotoxin shock in rabbits, comparable with PEC. These findings show that the two exotoxins are the same protein, which is assumed to be TST. When injected into rabbits, the culture supernatant of strain 587 showed biological activity like that described above, whereas the culture supernatant neutralized with anti-TST immunoglobulin did not. This showed that PEC-producing strain 587 does not produce any toxin with these biological activities in rabbits except TST.

Amino Acid Sequence↗
PubMed1983

[Combined action of cephamycin and aminoglycoside antibiotics].

The combined actions of cefoxitin (CFX) with amikacin (AMK), gentamicin (GM) and dibekacin (DKB) were studied against Gram-positive and Gram-negative bacteria. The following results were obtained. The synergistic actions of CFX with AMK, GM and DKB were observed on S. aureus, S. epidermidis, E. coli, S. marcescens, K. pneumoniae, Proteus spp. and Acinetobacter by checker board titration method. The combination of CFX with AMK was most effective. In case of the combination of CFX with AMK, the simultaneous administration showed the highest bactericidal effect, followed by the case of addition of AMK after adding CFX. The phase-contrast microscopic observation on S. marcescens revealed that the bacterial cell prolonged with CFX showed a filament-like form and with AMK almost a normal form. In the combination, lysed cells were observed. The therapeutic experiment of S. marcescens infection in mice demonstrated that the combination of CFX with AMK showed superior effect than that of each drug alone.

Amikacin↗
PubMed1982

Ferensimycins A and B. Two polyether antibiotics. Taxonomy, fermentation, isolation, characterization and structural studies.

Ferensimycin A* (I), C34H59O10Na, mp 133 approximately 135 degrees C, and ferensimycin B** (II), C35H61O10Na, mp 143 approximately 145 degrees C, were isolated as their sodium salts from the fermentation broth of Streptomyces sp. No. 5057, a strain similar to Streptomyces myxogenes Shomura et al. The physicochemical data of I and II showed that they are both closely related congeners of lysocellin (III). Ferensimycins A and B exhibit activity against Gram-positive bacteria and are effective in the treatment of coccidiosis of fowl.

Animals↗
PubMed1981

Ultrasonic degradation of schizophyllan, an antitumor polysaccharide produced by Schizophyllum commune Fries.

Schizophyllan, a water-soluble beta-D-glucan elaborated by Schizophyllum commune Fries, was partially depolymerized by ultrasonic irradiation to a low-molecular-weight polysaccharide, designated "sonic-degraded schizophyllan". Both native and degraded polysaccharides exhibited essentially the same antitumor activities against Sarcoma-180 ascites. Both glucans are comprised solely of D-glucose residues and have a main chain of (1 leads to 3)-beta-D-glucopyranosyl residues, one out of three glucose residues being attached as single, (1 leads to 6)-beta-D-glucopyranosyl groups. Although both glucans have similar structural features, significant differences are observed in such physical properties as molecular weight and intrinsic viscosity. End-group analysis by using radioisotope-labeled glucans suggests that ultrasonic degradation occurs mainly by cleavage of glycosidic bonds of the main chain of schizophyllan. The molecular weights of the native and sonic-degraded schizophyllan were shown to be 75% of those of corresponding, original schizophyllan preparations, suggesting that there is no anomalous linkage sensitive to periodate oxidation, and ultrasonic irradiation may cause random hydrolysis of (1 leads to 3)-beta-D-glucosidic linkages in the main chain.

Animals↗