Degenerative changes in properties of the mitochondrial inner membrane in pea cotyledons during germination

Mitochondria isolated from 5-day-old pea cotyledons had lowrespiration activity and did not respond to exogenous ADP, whilethose from 1-day-old cotyledons respired actively and respondedto ADP. The former mitochondria, but not the latter, were verysusceptible to destruction during extraction and purification.The mitochondrial inner membrane isolated from 5-day-old cotyledonswas less dense than that from 1-day-old cotyledons. The specificactivity of SDH in the former membrane was lower than that inthe latter, while both membranes were similar to each otherwith respect to the specific activity of Cyt ox. Disc electrophoresisof solubilized membrane on polyacrylamide gel containing SDSshowed that the mitochondrial inner membrane from 5-day-oldcotyledons contained lesser amounts of several polypeptidescompared with that from 1-day-old cotyledons. Such alterationsin the mitochondrial inner membrane were not observed with theexcised cotyledons cultivated for 5 days. (Received June 17, 1977; )