Purification and characterization of an agglutinin in the red alga Agardhiella tenera.

The red alga, Agardhiella tenera was found to contain a glycoprotein which agglutinates mouse leukemia cells, L5178Y but not L1210. It also agglutinates guinea pig and rabbit erythrocytes, and has weak activity against human A, B and O, mouse, horse and sheep erythrocytes and hamster and mouse lymphocytes. The agglutination was not inhibited by simple sugars. The major active component was purified and determined to be a beta-structure protein containing 2.7% glucose as sugar moiety. The molecular weight was estimated to be 12,000 by gel filtration and 13,000 by polyacrylamide gel electrophoresis, in the presence of sodium dodecylsulfate. Its isoelectric point was 6.1, and it contained high amounts of glycine, serine and threonine, but no half cystine or histidine. It had no subunit structure, and the C- and N-terminal amino acids were threonine and arginine, respectively.