Fig. 5-8. Thermal inactivation of S-proteins. 

 Purified extracts containing the S-proteins were heated 

 at 30°C (•),40°C (a), or 50°C (■) from 5 to 25 min, then 

 assayed at 25°C at saturating substrates. A) SP-I (4 ng 

 protein) was assayed for SDH activities at various 

 temperatures. B) SP-I I (6 ng protein) was assayed for 

 SDH activity at various temperatures. 



