1. Based on what you have learned so far in your biology classes, make a hypothesis about which of the three tissues (skeletal muscle, kidney, liver) has the highest level of SDH activity, giving a rationale for your hypothesis.
2. State your hypothesis about the effect of malonate on SDH activity.
3. Do you expect the SDH from all three homogenates (skeletal muscle, kidney, liver) to be equally sensitive to malonate? Explain.
1] SDH or succinate dehydrogenase also called respiratory Complex II, is an enzyme complex found in the inner mitochondrial membrane of eukaryotic cells. It is the only enzyme that participates in botch, the citric acid cycle and the electron transport chain.
Considering the function of SDH, it seems logical that SDH activity will be highest in the skeletal muscles. This will be so because the skeletal muscles produce and consume the highest amount of energy among the three given tissues.
2] Malonate works to inhibit the activity of SDH. Malonate binds to the active site of the enzyme but no reaction takes place. Since it blocks the active site, succinate is not able to bind. Thus, malonate acts as a competitor of succinate, which is the usual substrate of SDH. So, malonate decreases the rate of cellular respiration.
3] Yes.
Because the activity of malonate does not depend on which cell it is found in. It is the chemical structure of the malate molecule and its ability to bind to the active site of SDH which blocks the action of succinate. The type of cell they are present in will not determine their activity.
1. Based on what you have learned so far in your biology classes, make a hypothesis...