text: what is the effect of temperature pespin activity and effect of ph on pespin activity? in regards of using boiled eggs- cutting them into four equal pieces and placing 1 piece in each test tube. 2 pieces are covered with pepsin in dilute acid. one goes into the incubator and the other in the refrigerator. the other two pieces are covered with pepsin in alkali and one piece goes in the incubator and the other in the refrigerator. disregard those in alkali: they cannot work! pepsin is in the stomach thus its optimum ph is acidic. you ar now left with two. the one in the fridge cant work well as enzyme activity is slowed by low temperature. thus the one that would digest the egg is the one in acid, in the incubator as these conditions are optimum for pepsin's activity.