Substrate- and ligand-induced conformational changes were studied in a series of thiol-modified derivatives of rabbit muscle creatine kinase that retained different amounts of enzymic activity. The results indicate that the 'reactive' thiol group of the enzyme is required for the conformational changes associated with formation of a 'transition-state analogue' complex.

The crystal structure of rabbit muscle creatine kinase, solved at 2.35 A resolution by X-ray diffraction methods, clearly identified the active site with bound sulfates surrounded by a constellation of arginine residues. The putative binding site of creatine, which is occupied by a sulfate group in this analysis, has been tentatively identified. The dimeric interface of the enzyme is held toget...

Earlier studies showed that there is significant creatine kinase activity in the epiphyseal growth cartilage, and there is stage-specific isoform expression. To further explore the role of this enzyme in cartilage development, we disrupted the creatine kinase creatine phosphate (CK-CP) circuit using the creatine analogue, cyclocreatine. We found that while cyclocreatine decreased creatine kinas...

The interference of atypical creatine kinase (CK; EC 2.7.3.2) with anion-exchange methods for the measurement of the CK-MB isoenzyme is now firmly established. False-positive results from this source are much more common than interferences caused by the BB isoenzyme. Atypical CK, at least in some patients, does not appear to be a genetic variant, nor could we relate it to a specific clinical di...

A 20-year-old man was found to have high plasma creatine kinase (EC 2.7.3.2) activity in association with a rhabdomyosarcoma of the prostate. There was a very high proportion of the MB isoenzyme. Clinical findings and changes in creatine kinase activity with time showed that this increase was not ascribable to myocardial disease. We believe that the high proportion of CK-MB, confirmed by a comb...

BACKGROUND The CF transmembrane conductance regulator (CFTR), whose mutations cause cystic fibrosis (CF), depends on ATP for activation and transport function. Availability of ATP in the cell and even more in specific cellular microcompartments often depends on a functional creatine kinase system, which provides the 'energy buffer' phosphocreatine. Creatine supplementation has been shown to inc...

Creatine Kinase and the Correlates of Blood Pressure in a Random Population Sample To the Editor: We hypothesized that creatine kinase (CK), the central regulatory enzyme of energy metabolism, amplifies blood pressure responses, and subsequently showed that CK activity is independently associated with blood pressure.1 CK catalyzes the reversible transfer of the high-energy phosphate moiety (P) ...

Abbreviations: GSTs: Glutathione S-Transferases; DM: Myotonic Dystrophy; PROMM: Proximal Myotonic Myopathy; ROS: Reactive Oxygen Species; Ile: Isoleucine; Val: Valine; EMG: Electromyographia; NCV: Nerve Conduction Velocity; OD: Optical Density; SNP: Single Nucleotide Polymorphisms; LWD: Learning and Writing Disability; SLD: Speech and Languages Disability; SCK: Serum Creatine Kinase; CK-MM: Cre...