BIOCHEMICAL METHODS FOR THE STUDY OF NITROGEN METABOLISM IN PLANTS

Abstract

A method of preparing plant sap for analysis is suggested which eliminates the uncertainty of extraction and precipitation methods. Hydrolysis of amide N is accomplished without humin formation by hydrolyzing with 20% Na bisulphite in a steamer for 3 hrs. Hydrolysis of N compounds between proteins and amino acids by an enzyme solution containing proteinase, carboxy-poly-peptidase, aminopolypeptidase, and di-peptidase is also accomplished without humin formation. The error in phosphotungstic acid precipitation and "other nitrogen" owing to the presence of peptides, etc., is eliminated by the hydrolysis procedure. Determination of [alpha] amino N before and after hydrolysis may be used as a more accurate method of determining peptide N than precipitation methods.