The effect of gastrointestinal surgery on serum creatine kinase activity was studied in 30 patients. The MB isoenzyme was demonstrated in sera of 30% of the patients and BB isoenzyme in 23%. MB content varied from 0.8 to 10.3% of the total creatine kinase activity, and the BB content from 0.6 to 18.4%. The CK-BB was probably of gastrointestinal origin, since gastrointestinal tract contains high...

We describe a case of a limb-girdle myopathy presenting with myoglobinuria. A partial deficiency of muscle carnitine palmitoyltransferase (EC 2.3.1.21) may also have been present. All "muscle-type" serum enzymes were markedly increased (to between 30- and 400-fold their respective upper reference limits) and creatine kinase (EC 2.7.3.2) isoenzyme 2 (CK-MB) was increased 130-fold but was still l...

We assessed the reported presence of creatine kinase-BB isoenzyme in the serum of patients with chronic renal failure. Our study showed that the blood of these patients contains a fluorescent material with an electrophoretic mobility similar to that of the BB isoenzyme on cellulose acetate strips. The fluorescing material is, however, completely distinct from BB isoenzyme and its nature is as y...

We describe a spectrophotometric kinetic assay for detecting creatine kinase MB isoenzyme activity in the 1 to 10 U/liter range. The MB isoenzyme was isolated [Clin. Chem. 20, 36 (1974)] and assayed (Rosalki method) with an Abbott ABA-100. Good reproducibility was demonstrated for MB isoenzyme activities near 1 U/liter (CV = 2.6%). Sera with normal or slightly increased total creatine kinase ac...

With p-nitrophenyl phosphate as the substrate, there reportedly is no organ-specific inhibition of alkaline phosphatase (EC 3.1.3.1) activity by L-phenylalanine. However, we found that at pH 10.0, with p-nitrophenyl phosphate as the substrate, L-phenylalanine obviously inhibits the alkaline phosphatase isoenzyme from human placenta, whereas there is little if any inhibition of the isoenzyme fro...

The isoenzymic forms of branched-chain amino acid aminotransferase in mitochondria of rat tissues were compared with the better-known cytosolic forms in order to find any regular pattern of expression of these isoenzymes during development. Mitochondria of all tissues examined except brain contained only a type-I isoenzyme differing from the cytosolic type-I isoenzyme in heat stability and acti...

We observed an unexpectedly high incidence of the D-variant placenta! phenotype in Regan isoenzyme-positive sera of cancer patients-. Such D-variant-positive sera exhibit a high degree of inhibition by L-leucine, a phenomenon earlier associated with the Nagao isoenzyme. Unlike normal pla centae, a diffuse phenotype of heat-stable alkaline phosphatase is usually noted in cancer sera containing N...

In serum obtained from 28 women before, during, and after normal labor and delivery, creatine kinase activity was seen to be distinctly elevated immediately after labor and 24 h later, but had returned to normal six weeks later. In most cases the increase was due to the MM isoenzyme and was attributed to skeletal-muscle damage associated with labor. In 15 cases, the BB isoenzyme was observed, a...

Creatine kinase isoenzyme MB catalytic activities in human serum, determined by ACA ion exchange chromatography and immunoinhibition, differ significantly, the correlation coefficient being 0.88. The reasons for this variation are interference of antibodies with the creatine kinase B subunit in the immunoinhibition assay, nonreproducible elution of creatine kinase isoenzyme MB from the ion exch...

A steady-state kinetic method has been revised for measuring lactate dehydrogenase isoenzyme activities, which relates the inhibition of heart-type isoenzyme activity to the overall isoenzyme composition of the enzyme subunits. The method depends on the pH-dependent formation of an inhibitory ternary complex by the heart-type isoenzyme with NAD+ and pyruvate (if the reaction is measured by NADH...