Isolation and Spring Mobilization of Proteins in Citrus Trees (Citrus unshiu Marc.)

Abstract

SummaryThe proteins of the stem bark, stem wood and leaves of 23-year-old satsuma mandarin trees were separated into tris-soluble, alkaline-soluble and insoluble proteins. The tris-soluble proteins were separated further into five and six groups, using gel filtration and DEAE-cellulose column chromatography. Variations in the fractionated protein group were examined during spring and summer. Most of the proteins isolated, contributed to nitrogen mobilization in varying degrees. In leaves a protein of molecular weight of about 55, 000 showed the largest decrease. Amino acid analysis of six protein groups from the tris-soluble proteins of the bark showed no difference in their amino acid composition. The nitrogen storage function of proteins is discussed.