Cytochrome P-45Oj has been purified to electrophoretic. homogeneity from hepatic microsomes of adult male rats administered ethanol and compared to the corresponding enzyme from isoniazid-treated rats. The enzymes isolated from ethanoland isoniazidtreated rats have identical chromatographic properties, minimum molecular weights, spectral properties, peptide maps, NHz-terminal sequences, immunoc...

The isozyme patterns and activities of six enzymes were determined in surgical biopsy samples of lung tumors and non-neoplastic pulmonary areas. Fetal lungs were also examined. No tissue differences were found in the isozyme pattern of hexokinase or alkaline phosphatase; small differences in pyruvate kinase isozyme proportions were observed. The tumors exhibited significant deviations with resp...

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 ...

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...