The Identity of the Metachromatic Substance of Basophilic Leucocytes

The metachromatic anionic polysaccharides of basophilic leucocytes from a patient with chronic myeloid leukaemia displaying a very high basophilic leucocyte count has been examined. A polysaccharide containing glucosamine was isolated. It was resistent to testicular hyaluronidase but sensitive to bacterial heparinase and incorporated (35S)‐sulphate and (14C)‐glucosamine indicating its identy with heparin. Density gradient centrifugation of the cells showed that the heparin‐like substance was present in the basophilic leucocytes. Gel chromatography demonstrated that only the largest molecules of the polysaccharide population incorporated (14C)‐glucosamine while a pool of smaller molecules remained unlabelled.