79 



pooled samples containing DQT/SDH activities were 

 concentrated and examined for possible differential 

 properties, substrate requirements for saturation with SHK 

 and NADP% alternative substrate specificities (i.e., NAD* 

 and QA) , temperature optimum, thermal inactivation, SDS PAGE 

 and activity-stained native PAGE. No significant 

 differences were found between the overlapping peak samples 

 of I to V (data is not shown) . All six protein samples were 

 specific for NADP* and SHK when assayed for SDH activity. 

 Pool sample IV (or perhaps I through V) corresponds to SP-I, 

 and Peak VI corresponded to SP-II. SP-I and SP-II exhibited 

 similar properties except for Mj., Km and activity stained 

 gels. 

 Molecular Mass 



A difference was seen in the molecular mass of SP-I and 

 SP-II as shown in Fig. 5-2. SP-I migrated slightly ahead of 

 SP-II on SDS gels (A) and on a silver stained SDS gels (B) . 

 Both gels showed bands (or set of bands) at about 59 kD and 

 40 kD for purified SP-I, and bands at about 61 kD for 

 purified SP-II. A band at 42 kD can be detected when higher 

 concentration of SP-II was used in these experiments. The 

 silver stained gel offered higher resolution and indicated 

 that the affinity purified SP-I also had a set of bands at 

 about 29 kD. Native M,. was determined on a Sephadex G-200 

 column, ( Fig. 5-3, panels A and B) , to be about 59 kD and 62 

 kD for SP-I and SP-II, respectively. In crude extract 



