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Biomedical subjects

K Kuroda

Publications and source records attributed to K Kuroda.

At least 451 records · Page 25Linked to original sources
PubMed1980

Absence of transcellular fluid shift during haemofiltration.

Total body and extracellular fluid volume before and after haemofiltration were calculated using urea and inulin as markers. The change in plasma volume and interstitial fluid volume were also evaluated by haemoglobin concentration and hematocrit value. The extracellular fluid volume, especially interstitial fluid volume, was reduced, while intracellular fluid volume was not altered by haemofiltration.

Blood↗
PubMed1980

Racemization in peptide synthesis. A laboratory experiment for senior undergraduates.

A laboratory experiment involving the coupling of N-benzoylamino acids with methyl N epsilon-benzyloxycarbonyl-L-lysinate using various methods is described. The extents of racemization are determined by analysis for the protected diastereomeric dipeptide ester products by quantitation of the separated ester methyl proton peaks of their nuclear magnetic resonance (60 MHz) spectra. Synthesis of the starting materials and additional exercises are included as options.

Benzyl Compounds↗
PubMed1979

Physicochemical properties of pyocin F1.

The physiochemical properties of pyocin F1 were studied. Pyocin F1 consists of flexuous rod-like particles homogenous in size. Each particle was composed of rod and fiber parts. The rod part was 105.5 +/- 9.5 nm long and 10.0 +/- 1.4 nm wide, and showed regular striations amounting to 23 layers. The fiber part was composed of several filaments; the length of the longest filament was 43.0 +/- 12.0 nm. The amino acid composition, the partial specific volume (0.720 ml/g), the sedimentation coefficient (S020,W = 35.1S), and the translational diffusion constant (0.94 +/- 0.01 x 10(-7) cm2/s) were determined. The particle weight was calculated to be 3.23 x 10(6) daltons.

Amino Acids↗
PubMed1979

Biochemical properties of a new flexuous bacteriocin, pyocin F1, produced by Pseudomonas aeruginosa.

Pseudomonas aeruginosa strain P15 produces not only pyocin R1 and phage PS10, but also a substance having a flexuous rod structure, the nature of which is so far unknown. A variant strain (P15--40) was obtained which produced these flexuous particles more effectively than the original strain, and the particles were purified to homogeneity and investigated. Several strains of P. aeruginosa were found to be killed by the particles. It was concluded that the flexuous rod-like particles are not related to pyocin R1 or phage PS10, but represent a new pyocin, which we have designated as pyocin F1. Pyocin F1 showed a different action spectrum and a different pattern on SDS-polyacrylamide gel electrophoresis from either pyocin R1 or phage PS10. The killing activity of pyocin F1 was of single-hit type. The activity was not affected by anti-R1, anti-R1-core or anti-PS10, or by DNase, RNase, pronase or trypsin, but was completely destroyed by treatment at 70 degrees C for 10 min. Some cofactor was required for the adsorption of this pyocin on sensitive bacteria. Another flexuous bacteriocin was also found and named pyocin F2.

Bacteriocins↗
PubMed1979

A series of lysyldipeptide derivatives for racemization studies in peptide synthesis.

The series of diastereomeric peptide derivatives N-benzoyl-D,L-X-N epsilon-benzyloxycarbonyl-L-lysine methyl ester where X = alanyl, valyl, leucyl, phenylalanyl and isoleucyl are submitted as model systems for studying racemization in peptide synthesis. The diastereomers can be analyzed by quantitation of the separated ester methyl proton peaks of their nuclear magnetic resonance spectra. Data on the tendency to racemize of the different residues are presented. In polar solvents, valyl and isoleucyl residues racemize more readily than the other residues.

Amino Acids↗
PubMed1979

Lysyl dipeptide and tripeptide model systems for racemization studies in amino acid and peptide chemistry.

Four series of diastereomeric peptide pairs (X-Lys, Lys-Y, Gly-X-Lys, and Gly-Lys-Y; where X and Y = Ala, Leu, Val, Ile, Phe, and Pro) have been synthesized by conventional procedures using benzyl-based protecting groups. Chromatographic separation of each pair, except Gly-Lys-Pro, has been achieved by elution from a 15-cm Aminex A-5 resin column using pH 5.5 buffer for tripeptides, pH 6.5 buffer for dipeptides, and pH 7.5 buffer for phenylalanyl peptides. The isomers have been identified by chromatography of the L-L isomers. Examples of the use of the model peptides for optical purity determinations and as tests for racemization are presented. The series Gly-X-Lys allows comparison of the tendencies to racemize of residues X during couplings. The separations of other peptides where Y = MeVal and X = N- and O-methylhydroxyamino acids are also described.

Amino Acids↗