We examined the reaction surfaces around five variables (imidazole, ADP, creatine phosphate, magnesium, and pH) in the Scandinavian method for determining creatine kinase, using factorial experimentation (five level, five factor) at reaction temperatures of 30 and 37 degrees C. Theoretical response surfaces were computed by fitting a quadratic polynomial equation to the experimental data by lea...

catalyzed by adenosine triphosphate-creatine transphosphorylase can be described by a reasonable kinetic scheme. It was shown that MgATPzis the “true substrate,” that the Michaelis constant is the dissociation constant of the enzyme-substrate complex, and that the pH-activity curve resembles a single ionization curve with pK N 6.5. It was of interest to study the kinetics of the reverse process...

1. Leg blood flow, uptake of oxygen and glucose and release of lactate by the leg and changes in intramuscular concentrations of metabolites were studied at rest and during exercise of increasing work loads in thirteen patients with occlusive disease of the iliac or superficial femoral arteries. 2. Leg blood flow (dye-dilution technique) and oxygen uptake during exercise were low and levelled w...

SERUM CREATINE KINASE activity has beell measured by determining the amount of creatine liberated in the following reaction: ADI + creatine phosphate ATP + creatine. The Voges-Proskauer reactioii, production of a color by reaction of creatille with diacetyl alid -naphthol, has heeii used to measure enzymatically released creatine (1-5). The presence of a sulfhydryl compound in tile incubatioii ...

Deficient bioenergetic signaling contributes to myocardial dysfunction and electrical instability in both atrial and ventricular cardiac chambers. Yet, approaches capable to prevent metabolic distress are only partially established. Here, in a canine model of tachycardia-induced congestive heart failure, we compared atrial and ventricular bioenergetics and tested the efficacy of metabolic rescu...

2. Tests with known mixtures of phosphate esters and the recovery of the phosphorus of muscle extracts from the chromatograms suggest that the individual values obtained with the method in its present form are reliable to within 10 %. 3. Trichloroacetic acid extracts of muscle have been found to contain certain phosphate esters not yet identified. 4. The pyrophosphate fraction present in the ex...

BACKGROUND AND OBJECTIVES Patients with rheumatoid arthritis (RA) frequently suffer from muscle weakness. Oral administration of creatine has been shown to improve muscle strength in healthy subjects. The objective of this study was to examine the effect of oral creatine supplementation on muscle weakness, disease activity and activities of daily living in patients with RA. METHODS During a p...

The reaction catalyzed by rabbit muscle creatine kinase ATP + creatine in equilibrium ADP + P-creatine has been investigated by 31P NMR. At pH 8.0 and 4 degrees C, the equilibrium constant of the overall reaction [P1][P2]/[S1] [S2] is found to be 0.08, while that for the interconversion step between enzyme-bound substrates and products [E.P1. P2]/[E.S1.S2] is estimated to be approximately 1; th...

Background Nicotine, cotinine and cadmium are harmful components of cigarettes that have an effect on human reproductive function. Although the effects of cigarette smoke on male reproductive function is characterized in several articles its mechanism of action is still unknown. In the present study, we investigate the effect of nicotine, cotinine and cadmium on human sperm creatine kinase acti...