1. Kinetic data concerning the substrate and product inhibition by pyruvate and L-lactate have been obtained with the Md and Hd fractions separated from crystalline rabbit muscle lactic dehydrogenase. 2. The studies indicate that the product inhibition by L-lactate or by pyruvate is predominantly noncompetitive for both the Mq and Hq isozymes. Ki values for product inhibition by L-lactate were ...

To determine whether kinase (TK) isozyme status adds clinically useful information in adult non-Hodgkin's lymphoma (NHL), we have analyzed peripheral blood plasma and lymphocytes of 44 patients with NHL for either TK1 or TK2 isozyme activity. On the basis of isozyme status, patients could be divided into two groups that did not differ significantly with respect to known determinants for surviva...

The hydroxylation of prostaglandin (PG) E1, PGE2, and PGA1 was investigated in a reconstituted rabbit liver microsomal enzyme system containing phenobarbital-inducible isozyme 2 or 5,6-benzoflavone-inducible isoenzyme 4 of P-450, NADPH-cytochrome P-450 reductase, phosphatidylcholine, and NADPH. Significant metabolism of prostaglandins by isozyme 2 occurred only in the presence of cytochrome b5....

Four distinct isozymes of aspartate-alpha-ketoglutarate transaminase in a spinach (Spinacia oleracea L.) leaf extract were separated by starch gel electrophoresis. Of the total aspartate-alpha-ketoglutarate transaminase activity, approximately 45% was represented by the chloroplast isozyme, 26% by the cytosol isozyme, 19% by the mitochondrial isozyme, and 3 to 10% by the peroxisomal isozyme. Th...

The additional lactate dehydrogenase isozyme from rabbit testis and sperm, lactate dehydrogenase isozyme-1 (B4) from heart, and lactate dehydrogenase isozyme-5 (A4) from liver have been separated and partially purified by preparative starch gel electrophoresis. Studies performed on these fractions comprised K, and optimum substrate concentration for pyruvate, a-ketobutyrate, and lactate, inhibi...

Leucocyte alkaline phosphatase (LAP) is a granulocyte enzyme whose concentration varies in disease states. In order to determine whether the pattern of expression is altered in leukaemic granulocytes, we have analysed the LAP isozyme pattern of a series of normal subjects and patients with various haematological diseases. Electrophoretic patterns of partially purified LAP samples were determine...

The effects of Gö-6976, a Ca(2+)-dependent protein kinase C (PKC) isozyme inhibitor, and rottlerin, a PKC-delta isozyme/calmodulin (CaM)-dependent kinase III inhibitor, on responses to vasopressor agents were investigated in the feline pulmonary vascular bed. Injections of angiotensin II, norepinephrine (NE), serotonin, BAY K 8644, and U-46619 into the lobar arterial constant blood flow perfusi...

Leaf extracts of 27 `Yuzu' and related acid citrus cultivars were analyzed using polyacrylamide gel electrophoresis for isozyme variation of glutamate oxaloacetate transaminase (GOT) and shikimate dehydrogenase (SDH). SDH yielded 12 different isozyme phenotypes and six cultivars were discriminated by this enzyme alone. GOT produced 10 different isozyme phenotypes and four cultivars were separat...