The oxidative activity of particulate fractions from germinating castor beans

Abstract

Particulate preparations were prepared from the endosperm of germinating castor beans (Ricinus communis) which under appropriate conditions will oxidize the various intermediates of the Krebs cycle at hgih and sustained rates. The activity of such preparations is related to the stage in germination, and a decline in activity which occurs after the 4th day was shown to be due to the presence of the thermolabile factor. A study was made of the effects of added cofactors on the oxidation of the various acids by the Ricinus preparations. Clear requirements were established, not only for adenosine triphosphate and diphosphopyridine nucelotide but for the additional cofactors coenzyme A and cocarboxylase. An explanation was suggested for the apparent stimulation by cofactors of the oxidation of individual acids in which no primary role for these substances has yet been established.