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Biomedical subjects

J Noguchi

Publications and source records attributed to J Noguchi.

At least 91 records · Page 5Linked to original sources
PubMed1986

Neuraminidase and hematopoietic factors from human urine.

Human urinary neuraminidase, an enzyme that releases sialic acid from hematopoietic factors found in urinary preparations, was partially characterized, and a method was developed to derive these hematopoietic factors free of enzyme activity. Neuraminidase in urinary preparations from healthy humans and aplastic anemic (AA) patients had optimal activity at pH 5.3 and hydrolyzed both alpha 2----3 and alpha 2----6 type ketosidic linkages of N-acetyl-neuramin lactose and alpha 1-acid glycoprotein. When subjected to Sephacryl S-300 gel filtration, urinary neuraminidase showed a single peak of activity with an apparent molecular weight of 380,000 daltons, even under denaturing conditions (6 M guanidine hydrochloride). Furthermore, among a variety of compounds tested, no potent inhibitor of the enzyme was found. Heat treatment of AA urinary preparations eliminated about 80% of neuraminidase activity, while successive two-step ethanol precipitation eliminated residual enzyme. Erythropoietin, megakaryocyte colony-stimulating factor (CSF) and granulocyte/macrophage phage CSF activities were retained after these treatments.

Anemia, Aplastic↗
PubMed1983

Low-dose procainamide: low risk of complications with long-term use.

The incidence of procainamide-induced drug reactions was studied prospectively in 55 patients receiving long-term therapy with a mean duration of 23 months. New symptoms that occurred in 13 patients after the drug was started were similar to complaints presented by 25 patients before the medication was started. Duration of therapy was positively correlated with new symptom occurrence (P < .05) but not with age, sex, dose, or dose interval. Other concomitant drugs did not influence the results. Antideoxyribonucleoprotein antibodies were positive in 27 patients (55 percent) and in seven of 13 with new symptoms; female sex (P < .05) and increasing age (P < .05) favored a positive test. Anti-DNA antibodies were not found in any patients. Procainamide, at a mean dose of 1.5 g/day, was judged to be therapeutically effective by the clinic staff independent of this study; the drug was not discontinued in any patient because of the severity of symptoms.

Adult↗
PubMed1979

The action of trypsin on synthetic chromogenic arginine substrates.

A new arginine derivative, N-benzyloxycarbonyl-L-phenylalanyl-L-valyl-L-arginine-p-nitroanilide hydrochloride (ZPVAPA.HCl) was synthesized by the condensation of N-benzyloxy-carbonyl-L-phenylalanyl-L-valine and L-arginine-p-nitroanilide dihydrochloride using dicyclohexylcarbodiimide as a coupling reagent and 1-hydroxy-benzotriazole as an additive. L-ZPVAPA.HCl was split by trypsin more readily than Na-benzyloxycarbonyl-L-arginine-p-nitroanilide hydrochloride (L-ZAPA, HCl), Na-benzoyl-L-arginine-p-nitroanilide hydrochloride (L-BAPA.HCl), Na-tosyl-L-arginine-p-nitroanilide hdyrochloride (L-TAPA.HCl) and Na-benzoyl-DL-arginine-p-nitroanilide hydrochloride (DL-BAPA.HCl) by factors of 100, 400, 600, and 1,200, respectively. Low concentrations of dimethyl formamide (DMF) enhanced the trypsin-catalyzed hydrolyses of L-ZAPA.HCl and L-TAPA.HCl, contrary to the findings of other authors that DMF has no effect on the tryptic hydrolysis.

Arginine↗
PubMed1977

Studies on the catalytic action of poly-alpha-amino acids. VII. Stereospecificity in the enzyme-like hydrolysis of benzoyl-L-(D)-arginine-p-nitroanilides by copoly (Cys, Glu).

The substrate specificity in the hydrolysis of L-, DL-, and D-BAPA (benzoylarginine-p-nitro-anilide) by copoly (L-Cys, L-Glu) and copoly (D-Cys, D-Glu) was studied, and enzyme-like stereospecific hydrolyses by poly-alpha-amino acids were identified for the first time. The L-type copolymer hydrolyzed L-BAPA faster than D-BAPA and the rates (v) of BAPA hydrolyses by L-type copolymer were found to be in the order vL greater than vDL greater than vD. On the other hand, the D-type copolymer hydrolysed D-BAPA faster than L-BAPA and the rates of BAPA hydrolyses by D-type copolymer were in the order vD greater than vDL greater than vL. In all cases, the reaction followed Michaelis-Menten kinetics when the substrate concentration was corrected, and the optimum conditions of the reaction were pH 6.0 and 40 degrees. The activity appeared after a certain amount of BAPA had combined with the polymer. D- and L-substrates combine competitively with the polymer and the different rates of hydrolysis are presumably due to the different substrate configurations in relation to the conformation of the active site in the polymer. The polymer shows activity near the range of random coil conformation, where some alpha-helical conformation is still present. Only some of the cysteine residues in the copolymer are involved in the hydrolytic activity.

Arginine↗