1. Papadopoulos, N. M., and Hufnagel, C. A., Evaluation of lactate dehydrogenase isoenzyme patterns in serum of patients undergoing cardiac surgery. J. Thorac. Cardiovasc. Surg. 76, 173-177 (1978). 2. McKenzie, D., Clarke, P. I., and Henderson, A. R., How accurate are lactate dehydrogenase isoenzyme estimations by the thin-layer agarose fluorescent technique? Clin. Chem. 22, 1995-1998 (1976). 3...

The alkaline phosphatase activity expressed by JAR choriocarcinoma cells was compared to the placental isoenzyme of human alkaline phosphatase by several criteria. JAR cell alkaline phosphatase was similar to the placental isoenzyme with respect to heat and urea stability and sensitivity to most inhibitors, but it differed significantly from placental alkaline phosphatase in its sensitivity to ...

We describe an atypical serum creatine kinase isoenzyme in the serum of a woman with cancer of the left breast. This isoenzyme migrated toward the cathode, closely following the MM isoenzyme on agarose gel electrophoresis. Its relative molecular mass was estimated to be about 325,000, fourfold that of normal creatine kinase. It is more heat-stable and is inhibited more by urea than the normal M...

The method is based on the selective activating capacity of dithiothreitol on creatine kinase isoenzyme MB, after isoenzyme MM is activated by glutathione. Isolated isoenzymes MM and MB of human and canine origin were assayed individually and in mixtures of known activities. When glutathione was present in the assay medium the activity of each isoenzyme could be measured individually, but gluta...

The brain isoenzyme of creatine kinase (CK) (EC 2.7.3.2) has been identified in the serum of 21 of 950 patients tested. Samples were received over a period of about 20 months. Analysis was performed by electrophoresis on agarose gel with isoenzyme bands visualized by fluorescence after enzyme coupled reactions producing NADH. Specialized substrate preparations were used to rule out the possibil...

We compared an alkaline phosphatase (EC 3.1.3.1) isoenzyme from a plasma sample of a patient with carcinoma of the lung, who was suspected of having the Regan-type isoenzyme, with placental serum alkaline phosphatase and with tissue preparations from placenta, liver, bone, and intestine. The placental and Regan phosphatases responded similarly to heat treatment and modification by various inhib...

Since 1991, the Ontario Laboratory Proficiency Testing Program has assessed the analytical performance of creatine kinase (CK; EC 2.7.3.2) isoenzyme-2, using fresh human serum supplemented with purified human CK isoenzymes. In Ontario, the 142 laboratories licensed to analyze CK-2 use a variety of methods: electrophoresis-based, immunoinhibition, and mass assays. During a 1992 survey, duplicate...

The effect of dehydroepiandrosterone (DHEA) on the activity and isoenzyme patterns of liver glucose 6- phosphate dehydrogenase (G6PD) was investigated in rats during different stages of growth. G6PD activity of mature rats was less than those of the immature (43%) and newborn (35%) animals. DHEA at 10 M) inhibited G6PD activity of the mature , immature and newborn rats by 79%, 39% , and 88%...

Polyacrylamide gel electrophoresis (PAGE) was employed to examine the variation of ten isoenzyme markers in an attempt to assess the systematic and genetic relationships between Elymus repens, E. hispidus and their hybrid E. ×mucronatus. It was found that the hybrid shared most isoenzyme profiles and isoforms of its parents and high genetic affinity among the studied taxa was revealed. The isoe...

Electrophoretograms of atypical creatine kinase (EC 2.7.3.2, CK) isoenzymes may be difficult to interpret. In addition, their presence may cause discrepancies between results by immunological determinations for mass or activity and those by electrophoresis. Here we outline procedures to use in characterizing apparently atypical CK isoenzymes observed after electrophoresis, as illustrated by a C...