creatine kinase

creatine kinase /cre·a·tine ki·nase/ (ki´nās) an enzyme that catalyzes the phosphorylation of creatine by ATP to form phosphocreatine. It occurs as three isozymes (specific to brain, cardiac muscle, and skeletal muscle, respectively), each having two components composed of M (muscle) and/or B (brain) subunits. Differential determination of isozymes is used in clinical diagnosis.

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creatine kinase

n.

An enzyme present in muscle, brain, and other tissues of vertebrates that catalyzes the reversible conversion of ADP and phosphocreatine into ATP and creatine.

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creatine kinase (CK),

an enzyme of the transferase class in muscle, brain, and other tissues. It catalyzes the transfer of a phosphate group from adenosine triphosphate to creatine, producing adenosine diphosphate and phosphocreatine. The reaction stores energy in muscle and brain tissue. Also called creatine phosphokinase. See also Duchenne's muscular dystrophy.

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creatine [kre´ah-tin]

a nonprotein substance synthesized in the body from three amino acids: arginine, glycine (aminoacetic acid), and methionine. Creatine readily combines with phosphate to form phosphocreatine, or creatine phosphate, which is present in muscle, where it serves as the storage form of high-energy phosphate necessary for muscle contraction.

creatine kinase an enzyme catalyzing the transfer of a phosphate group from phosphocreatine to ATP. It has three isoenzymes: CK₁, found primarily in the brain; CK₂, found in the myocardium; and CK₃, found in both skeletal muscle and the myocardium. The presence of CK₂ in the blood is strongly indicative of a recent myocardial infarction; it is present until about 72 hours after the attack.

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creatine kinase (krē´tēn´ kī´nās´),

n an enzyme in muscle, brain, and other tissues that catalyzes the transfer of a phosphate group from adenosine triphosphate to creatine, producing adenosine diphosphate and phosphocreatine.

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creatine kinase

Creatine phosphokinase Internal medicine An 82 kD dimeric enzyme that catalyzes the reaction ATP + creatine = ADP + phosphocreatine, which exchanges high-energy phosphate and consumes energy; CK is concentrated in skeletal muscle, heart, brain; since CK levels peak 12-24 hrs after an MI and returns to normal by 48 hrs, specimen timing is critical Ref range 0-250 U/L. See Creatinine kinase isoenzymes.