A survey of lectin activity was made on the crude extracts of 15 species of locally
available marine invertebrates. Thirteen species were found to show lectin activity. The
body wall of Holothuria atra Jaeger, which had the highest lectin activity, was chosen for
further examination.
Lectin was extracted from the body walls of black sea cucumber (Holothuria atra Jaeger)
using Tris buffer saline (TBS) pH 7.5 containing 0.15 M NaCl and purified by ammonium
sulfate fractionation and gel chromatography using Sephadex G-200. The isolated lectin
was non-blood type specific as it agglutinated erythrocytes of all human blood types (A,
B, AB, O) and animal erythrocytes (calf, carabao, chicken and goat). Addition of trypsin
and calcium ions increased the agglutinating activity of both lectins.
The isolated lectin was found to be glycoprotein containing 0.50% total sugar. Based
on gel chromatography, the estimated molecular weight of lectin from the body wall is
439 kD. SDS-PAGE gave two protein bands for the isolated lectin with molecular weights