Creatine kinase and its isoenzymes in dog sera

Creatine kinase activity was determined in 103 clinically healthy dogs. Normal values of total creatine kinase and its isoenzymes have been established, and our method of electrophoresis is described. The normal range of the total-CK activity in dog was higher than that in man (up to 84 U./l in dog, up to 50 U./l in man). The electrophoretic pattern of isoenzymes was also different. The main isoenzyme found in dog serum was the CK-BB, and there was a minor, but evident band of the CK-MM fraction (up to 50 U./l). The CK-MB fraction in normal serum was not measurable (less than 1 U./l). The presence of the CK-BB fraction in serum of the dog, and the activities of single isoenzymes are discussed.