Cardiolipin monohydroperoxide

The reaction of PHGPx toward each substrate was analyzed by a HiU plot (Figure 7). The Hill coefficient was calculated to be 2.33 for cardiolipin monohydroperoxide and 1.37 for dihnoleoyl phosphatidylcholine... 

Figure 7. Hill plot analysis of PHGPx reaction. PHGPx activity was determined with either dilinoleoyl phosphatidylcholine monohydroperoxide (O) or cardiolipin monohydroperoxide ( ) as a substrate. The amount of PHGPx protein in a reaction mixture was about 0.4 pg.

The Km valne of PHGPx for dilinoleoyl phosphatidylcholine monohydroperoxide was 163 pM in the absence of cardiolipin. However, it deaeased to 70 pM in the presence of the activator cardiolipin. The values of Vmax are 11.9 and 17.8 mnol/min in the presence and absence of cardiolipin, respectively. 

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