HEMAGGLUTININS FROM POTATO LEAVES

Two types of phytohemagglutinins (PHA)(2) were isolated from leaves of potato plants Solanum tuberosum L. and Solanum chacoense Bitt.: soluble cytoplasmic phytohemagglutinins and membrane phytohemagglutinins isolated from the chloroplast thylakoid membranes. Like tuber lectins, the membrane phytohemagglutinins are specific to D-glucosamine and D-galactosamine. The ability of D-ribose-5-phosphate, ATP, and other nucleotides to inhibit hemagglutination is a specific feature of leaf membrane phytohemagglutinins. This ability decreases in the series ATP, ADP, and AMP. Phytohemagglutinins from the soluble protein fraction are not specific for any sugar or nucleotide tested. In contrast with leaf membrane phytohemagglutinins, the soluble leaf and tuber lectins interact with carbohydrates of immobilized chicken egg protein.