Malate dehydrogenase subunit structure

This dimeric enzyme (subunit 35000) catalyses a reaction similar to the lactate dehydrogenase reaction, and the subunit structures of the enzymes are strikingly similar [83-85] (Fig. 20). Crystallographic [85] and other [86] evidence suggests that the reaction mechanisms are similar. The 4-pro-R hydrogen of NADH is transferred to the Re side of the oxaloacetate to give L-malate [87],... 

Figure 9.8. The malate dehydrogenase dimer, indicating the location of the active sites in each protein plus the dimer interface. Malate dehydrogenase demonstrates substrate inhibition that has been attributed to subunit interactions and allosteric regulation by citrate, although the crystal structure of the protein reveals the absence of a separate allosteric site for citrate. See color insert.

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