the presence of high concentrations of compartmentalized ck isoenzymes within photoreceptor cells ( approximately equal to 30 enzyme units/mg ) as well as the relatively high concentration of total creatine in these cells ( approximately equal to 10-15 mm ) indicates an important physiological function for ck and phosphocreatine in the energy transduction of vision .
C0022173
isoenzymes
C0014442
enzyme