4343
A limiting factor were disturbances in the system of energy transport ( creatine phosphate , creatine phosphokinase ) and of the calcium pump ( Ca + + - ATPase of the sarcoplasmic reticulum , SPR ) , which evidently led to a decrease of the inotropic properties of the myocardium at 70 % restriction of coronary blood flow .
 creatine phosphokinase, Ca + + - ATPase
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 creatine phosphokinase, Ca + + - ATPase