The Metabolism of Nitrogenous Compounds by Sunflower Crown Gall Tissue Cultures.

Abstract

Investigation of the nitrogen metabolism of sunflower crown gall tissue cultures showed that although the tissue contained active glutamic acid-aspartic acid and glutamic acid-alanine transaminases, there was no correlation between the activities of these enzymes in crude tissue homogenates and the reported growth of the tissue at several levels of glutamate, aspartate, or alanine supplied the tissue in the medium. Nitrate had little effect on ammonia uptake by the tissues. Ammonia was an intermediate in the reduction of nitrate. When nitrate was supplied together with alanine, glutamic acid, aspartic acid or glycine, the tissue utilized both the nitrate and the amino acid. When tissue was incubated for short periods in a medium con-taining N15- labeled DL-alanine or DL-glutamic acid, the distri-bution of the N15 among the amino acids isolated from a tissue hydrolysate differed somewhat with the amino acid and with the concentration at which it was supplied. In general, however, glutamic acid was the most active amino acid, and alanine, aspartic acid, threonine, serine, methionine and phenylalanine were also highly active.