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H Doi

Publications and source records attributed to H Doi.

At least 325 records · Page 18Linked to original sources
PubMed1981

Presence of O-glycosidic linkage through serine residue in kappa-casein component from bovine mature milk.

This paper describes the glycosylation sites of kappa-casein component P-5 from bovine mature milk. A short glycopeptide was prepared from kappa-casein component P-5 containing two carbohydrate chains by pronase P digestion, followed by gel filtration and ion exchange chromatographies. The glycopeptide obtained corresponded to residues 128-141 (Gly-Glu-Pro-Thr-Ser-Thr-Pro-Thr-Thr-Glu-Ala-Val-Glu-Ser) of kappa-casein A from the results of analyses with chemical and enzymatic procedures. The effect of alkaline borohydride treatment indicated the presence of serine as well as threonine as the binding site of carbohydrate moieties. From the facts of Edman degradation and carboxypeptidase P hydrolysis of glycopeptide treated with alkali, the carbohydrate moieties were considered to be attached to threonine residue No. 133 and serine residue No. 141.

Amino Acid Sequence↗
PubMed1980

Experimental transmission of human subacute spongiform encephalopathy to small rodents. I. Clinical and histological observations.

Experimental transmission of subacute spongiform encephalopathy from three human cases to small rodents is reported. The first case with atypical CJD with spongiform change, kuru plaques, and leukomalacia was transmitted directly to mice, rats, and guinea pigs and indirectly to hamsters and Mongolian gerbils through rats. From two other typical SSE cases the disease was also successfully transmitted; from he second case to mice and rats, and from the third case to guinea pigs. Brain showed the highest infectivity; the spleen, liver, blood, and cerebrospinal fluid of diseased animals were also infective. Intracerebral inoculation was the route for the fastest transmission, followed by intrathecal, intraperitoneal, submucosal, and subcutaneous routes. The incubation periods and clinical features were characteristic in each inoculated species and did not vary within several passages, except for the shortening of incubation period from the first to the second passage. Histologically, a marked spongy state and proliferation of astrocytes were observed in all diseased animals, though the distribution of the lesion was peculiar to each species. The severe lesion in the white matter in mice was similar to that seen in mice inoculated with scrapie and also to that seen in the first case.

Aged↗
PubMed1979

Susceptibility of kappa-casein components to various proteases.

In order to clarify the function of the carbohydrate moiety of bovine kappa-casein, kappa-casein components having different carbohydrate contents were prepared by DEAE-cellulose chromatography. Five adsorbed fractions so obtained had an identical peptide chain and contained carbohydrate moieties of increasing size in the order of components P-2, P-3, P-4, P-5 and P-6. The subsceptibility of kappa-casein components, having different carbohydrate contents, to various proteases was examined. kappa-Casein components were subjected to calf rennin [chymosin; EC 3.4.23.4], bovine trypsin [EC 3.4.21.4], alpha-chymotrypsin [EC 3.4.21.1], pronase [EC 3.4.24.4] and human plasmin [EC 3.4.21.7]. The component containing a larger carbohydrate moiety was less susceptible to hydrolysis than the component containing a smaller carbohydrate moiety. Rennin, trypsin, alpha-chymotrypsin and pronase hydrolyzed each component with a different reaction rate. On the contrary, human plasmin hydrolyzed component P-2, but did not hydrolyze component P-5. These results indicate that the carbohydrate moiety of kappa-casein components to various proteases.

Carbohydrate Metabolism↗
PubMed1979

Minor components of reduced bovine kappa-casein.

Bovine kappa-casein reduced with 2-mercaptoethanol was fractionated on a DEAE-cellulose column to one nonadsorbed, five major adsorbed and two minor adsorbed fractions. The properties of the nonadsorbed and five major adsorbed fractions were reported in our previous paper (4). In this paper, the characteristics of two minor adsorbed fractions (P-X and P-Y) were reported. Gel electrophoretic patterns of these fractions were similar to kappa-casein. These fractions had the same amino acid composition and the same phosphorus content as the major components. P-X contained one residue each of N-acetylneuraminic acid, galactose and galactosamine, and P-Y two residues each. Furthermore, these fractions showed the stabilizing ability for alpha s1-casein in the presence of calcium ion. These results indicate that P-X and P-Y are minor components of reduced bovine kappa-casein.

Amino Acids↗