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Biomedical subjects

Y Endo

Publications and source records attributed to Y Endo.

At least 829 records · Page 46Linked to original sources
PubMed1977

The carbohydrate structure of a glycopeptide released by the action of plasma kallikrein on bovine plasma high-molecular-weight kininogen.

Fragment 1, released from bovine plasma high-molecular-weight kininogen by the action of plasma kallikrein, is a glycopeptide with approximately 3 mol of each of N-acetylgalactosamine, galactose and sialic acid in one molecule. All these sugars were in the T-1 fragment obtained by tryptic digestion of fragment 1. Sialic acid can be completely released from the T-1 fragment by sialidase digestion. When this sialic acid-free T-1 fragment was incubated with purified diplococcal endo-alpha-N-acetylgalactosaminidase, all remaining sugars were released as a disaccharide. By Smith degradation and beta-galactosidase digestion, the structure of this disaccharide was found to be Gal beta 1 leads to 3GalNAc. Methylation analysis of the trisaccharide released from fragment T-1 by alkaline borohydride treatment indicated that all the galactose was obtained as the 2,4,6-tri-O-methyl derivative. Based on this evidence, the complete structure of the carbohydrate moieties of fragment 1 was proposed as Sialyl alpha 2 leads to 3Gal beta 1 leads to 3GalNAc. In addition, small amounts of a tetrasaccharide, Sialyl alpha 2 leads to 3Gal beta 1 leads to 3(Sialyl alpha 2 leads to 6)GalNAc also occurred as a carbohydrate chain of fragment 1.

Animals↗
PubMed1976

Partial purification and properties of N-acetylhistamine deacetylase.

The enzyme catalyzing the deacetylaction of N-acetylhistamine was partially purified about 160-fold from rat liver extract and its properties were investigated. The purification procedure included DEAE-cellulose chromatography, precipitation with ammonium sulfate and DEAE-cellulose rechromatography. The enzyme contains a labile -SH group that is essential for its activity. Mn2+ and Co2+ enhanced the deacetylation reaction at low concentration. The molecular weight of the deacetylase was estimated to be about 70 000 from gel-filtration. Among various acetyl derivatives tested so far, N-acetylhistamine and to a lesser extent N-acetyltyramine served as the substrates. The Km value was 0.3 mM at the optimum pH 8.0 for N-acetylhistamine. Diphenhysramine, an antihistaminergic agent, inhibited the deacetylation remarkably.

Amidohydrolases↗
PubMed1976

Partial purification and characterization of an endo-alpha-N-acetylgalactosaminidase from the culture of medium of Diplococcus pneumoniae.

The culture medium of Diplococcus pneumoniae contains enzymic activity that cleaves Galbeta1 leads to 3GalNAc from desialized human erythrocyte membrane glycoprotein. The enzyme was purified 180-fold by ammonium sulfate fractionation, gel filtration through a Sephadex G-200 column, and DEAE A-25 Sephadex chromatography. The purified enzyme liberates Galbeta1 leads to 3GalNAc from glycopeptides and glycoproteins with Galbeta1 leads to 3GalNAcalpha1 leads to Ser and Thr moieties. The optimum pH of this enzyme is 6.0. Using glycopeptides obtained by trypsin digestion of human erythrocyte membrane glycoprotein as a substrate, a Km of 0.20 mM (on the basis of the amount of Galbeta1 leads to 3GalNAc residues) was obtained. So far, the enzyme appears to have a strict specificity for Galbeta1 leads to 3GalNAcalpha1 leads to Ser and Thr structures, because no oligosaccharides larger than trisaccharides were liberated from porcine submaxillary mucin.

Cations, Divalent↗
PubMed1976

Alpha fetoprotein in liver disease in Papua New Guinea.

A radioimmunoassay method was used for the detection of alpha fetoprotein (AFP) in the sera of 112 Papua New Guinean patients who had undergone liver biopsy. Sera from 69 normal subjects and 20 hospital patients were also tested. Alpha fetoprotein was found to be elevated above normal levels in many of these subjects, but particularly in those suffering from viral hepatitis, cirrhosis and primary liver cell carcinoma (PLC). The highest values were found in patients with PLC. It is concluded that because of the elevation of AFP values in all these different types of liver disease the RIA test is not of great value in Papua New Guinea, except in the follow-up of some patients with cirrhosis who are at risk of developing PLC and in those who have undergone treatment for PLC.

Carcinoma, Hepatocellular↗
PubMed1975

Synthesis of alpha-fetoprotein by rat ascites hepatoma cells.

AH-66 rat ascites hepatoma cells incorporated [14C]leucine into the AFP fraction. In a cell-free system, hepatoma ribosomes were found to be active in AFP synthesis whereas the supernatant fraction from hepatoma had no specific effect on AFP production. The amount of [14C]leucine incorporated in AFP by membrane-bound polysomes was 20 to 90 times higher than that by free polysomes, suggesting that AFP is mainly synthesized on membrane-bound polysomes. DBcAMP inhibited the growth of hepatoma cells. However, the incorporation of [14C]leucine into the AFP fraction as well as into total proteins was stimulated by DBcAMP.

Animals↗