Arginine metabolism by pumpkin seedlings. Separation of plant extracts by ion exchange resins

Abstract

Arginine-U-14C was injected into the cotyledons of 7-day old pumpkin seedlings. At most, 24% of the administered 14C was transported to the axis tissue. The amounts of arginine incorporated into cotyledonary protein suggests that turnover was occurring at a rapid rate. Arginine was extensively metabolized, and after 96 hr 50% of the administered 14C had been released as 14CO2. The remaining label was primarily in unmetabolized arginine, protein or transported to the axis tissue with little label in other amino acids. The results suggest that the carbon from arginine is incorporated into protein or catabolized to CO2 while the carbon for new amino acid skeletons is derived from sugar. A simple, reproducible method for the quantitative fractionation of plant extracts or hydrolysates of insoluble plant material into basic amino acids, acidic amino acids, neutral amino acids, organic acids and sugars was reported.