Tritium labelling of the lymphocyte - stimulating leucoagglutinin from kidney beans (phaseolus vulgaris)

Lymphocyte-stimulating leucoagglutinin isolated from extract of kidney beans (Phaseolus vulgaris) was labelled with tritium by treatment with acetic anhydride-3H in aqueous solution. The labelling procedure used, which introduced 1.7 acetyl groups per leucoagglutinin molecule (molecular weight: 140 000) had no detectable effect upon the lymphocyte-stimulating or agglutinating activity of the leucoagglutinin. The label was found to be stable after 2 months' storage at 4°C or °20°C.