The breakdown and synthesis of starch by an enzyme system from pea seeds

Abstract

The gradual elucidation of the intermediary role of phosphorylated sugars in the breakdown of carbohydrate by the enzymes of yeast and certain animal tissues forms an outstanding achievement in the field of the biochemistry of carbohydrates. It is attractive to suppose that the rapid interconversions of carbohydrates which occur in the higher plants may depends also upon the formation of labile phosphorylated derivatives of sugars. It cannot be claimed, however, that this view is supported by any extensive body of facts. Since so far as the higher plants are concerned, only fragmentary observations have been recorded on the occurrence and nature of phosphorylated sugars; relatively little is known may be present to act upon such esters. Investigations to be described in this and subsequent communications are directed towards various aspects of this metabolic problem. In the present paper it is proposed to consider a system of enzymes extracted from mature pea seeds which illustrates one type of mechanism by which phosphoric ester are formed in vegetable tissues. Further, the study of this system has disclosed the mechanism by which starch is synthesized in the plant.