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Biomedical subjects

C Yoshida

Publications and source records attributed to C Yoshida.

At least 73 records · Page 4Linked to original sources
PubMed1983

A new single band variant of the Gc subtypes determined by isoelectric focusing.

A new single band variant (Gc Ta) of the Gc subtypes which does not correspond with the known Gc variants has been detected in a healthy blood donor by isoelectric focusing. Using this technique the variant is represented by a single band, which is more cathodically located than the 1A8(fast) band and more anodically located than the 1A3(fast) band. It is well known that the single band Gc phenotypes remain unaltered after neuraminidase treatment. Nevertheless, the new single band variant (Gc Ta) is altered after neuraminidase treatment. In this case the new single band Gc variant also contained N-acetylneuraminic acid (NANA).

Blood Group Antigens↗
PubMed1982

Teratocarcinoma cell adhesion: identification of a cell-surface protein involved in calcium-dependent cell aggregation.

Teratocarcinoma cells have a Ca2+-dependent cell-cell adhesion site (t-CDS) that is unique in being inactivated with trypsin in the absence of CA2+ but not in the presence of Ca2+. Fab fragments of antibodies raised against teratocarcinoma F9 cells dissociated by treatment with trypsin and calcium (anti-TC-F9) inhibit the aggregation of teratocarcinoma cells mediated by t-CDS. This inhibitory effect of Fab is removed when anti-TC-F9 is absorbed with F9 cells treated with trypsin and calcium (TC-F9), but not when it is absorbed with F9 cells treated with trypsin and EGTA (TE-F9). Comparisons of cell-surface antigens reactive to anti-TC-F9 in TC-F9 cells with those in TE-F9 cells reveal that only one component, with an approximate molecular weight of 140,000 (p140), is detected specifically on the surface of TC-F9 cells. When TC-F9 cells are retrypsinized in the absence of CA2+, a substance with an approximate molecular weight of 34,000 (p34) is released that can neutralize the aggregation-inhibitory effect of the Fab. This p34 interferes with the immunoprecipitation of p140 with anti-TC-F9, suggesting that p34 is a tryptic fragment of p140. Anti-TC-F9 Fab causes the dissociation of the monolayers of teratocarcinoma cells. This effect is removed by absorption of the Fab with p34 as well as with TC-F9 cells, but not with TE-F9 cells. These results suggest that p140 is essential for the function of t-CDS, and that this is an actual cell-adhesion molecule active in the establishment of monolayers of teratocarcinoma cells.

Antigens, Surface↗
PubMed1982

Purification and properties of inorganic pyrophosphatase of rat liver and hepatoma 3924A.

Inorganic pyrophosphatase (EC 3.6.1.1) has been purified to electrophoretic homogeneity from the soluble portion of the cytoplasm of rat Hepatoma 3924A and rat liver. It has a specific activity of 600 to 700 mumol inorganic orthophosphate liberated per min per mg protein at 25 degrees, a value in the same range as the highly purified enzymes from yeast and Escherichia coli. By all criteria applied, the hepatoma inorganic pyrophosphatase is identical with the liver enzyme. It is a dimer with subunits with molecular weights of approximately 30,000 to 33,000 and has a pH optimum of 7.4, a Km for pyrophosphate of 5 microM, and a Ka for Mg2+ of 0.3 mM with a pyrophosphate concentration of 0.2 mM. It is not inhibited by high Mg2+ concentrations up to 20 mM. Other metal ions such as Zn2+ and Ca2+ do not activate. Mn2+ activates to less than 10% that of Mg2+ at 0.6 mM and has no effect at 1 mM or higher. In the presence of optimal (4 mM) Mg2+ concentration, Ca2+, Mn2+, Hg2+, and F- at 0.2 mM inhibited strongly, but Zn2+ at 1 mM was not inhibitory. The enzyme had no phosphatase activity toward any of the purine or pyrimidine nucleoside mono-, di-, and triphosphates or toward p-nitrophenyl phosphate, beta-glycerophosphate, glucose 6-phosphate, or glucose 1-phosphate. Bromo- or iodoacetate at high concentration had no inhibitory effect, but p-chloromercuribenzoate and p-chloromercuriphenylsulfonate inhibited strongly at low concentration. The purified enzyme was very unstable but was protected markedly at or above the pH optimum of 7.4 by cysteine, dithiothreitol, and glutathione.

Adenosine Triphosphate↗