The Enzymic Deamidation of Asparagine in the Higher Plants

Abstract

The authors believe that the role of asparagin as the form in which proteins are translocated in the plant has been established, but that the enzymic transformations involved have previously been undetermined. They were able to separate asparagin into NH3 and aspartic acid with an enzyme preparation from the roots of germinating barley. The preparation was also effective in the hydrolysis of glycyglycine, suggesting to the authors that a peptidase is involved. This assumption is strengthened by the fact that erep-sin from the intestine of the pig also caused the deamidation of asparagin. They conclude that the amide group in asparagin is peptide in nature and that the compound is essentially a dipeptide which could be produced in normal protein cleavage without the action of a special enzyme.