Fractionation of plant material. I. Extraction of proteins and nucleic acids from plant tissues and isolation of protein fractions containing hydroxyproline from broad bean (<i>Vicia faba</i> L.) leaves

Abstract

Abstract The proteins of broad‐bean leaves and stems dissolved readily and almost completely in phenol‐acetic acid‐water (2: 1 : 1, w/v/v) provided preliminary treatments of the material which allowed the formation of insoluble complexes by chemical and physical interactions were avoided. The proportion of the total nitrogen extracted from growing tissue by the phenol‐acetic acid‐water mixture varied inversely with the nucleic acid content of the tissue, which decreased with increasing age of the plant. Strong electrolytes in low concentration markedly increased the solubility of the nucleic acids in phenol‐acetic acid‐water mixtures. A non‐diffusible fraction, rich in hydroxyproline and soluble in cold trichloroacetic acid, was isolated. Hydroxyproline was also detected in the residue remaining after the phenol‐acetic acid‐water extractions. An unidentified compound giving a colour reaction with ninhydrin was also found in hydrolysates of the non‐diffusible material extracted by cold trichloroacetic acid from semi‐mature leaves.