Elevated sialyltransferase activity in the intestinal lymph of colchicine-treated rats

Abstract

There is a marked increase of sialyltransferase activity (EC 2.4.99.1) in serum and a profound change in the endogenous acceptor property of sialyl-transferase in the intestine of colchicine treated rats (Fraser, Ratnam, Collins and Mookerjea, (1980) J. Biol. Chem. 255, 6617–6625). To ascertain the contribution of intestine as a source of this elevated serum enzyme, sialyltransferase and other enzyme activities were measured in intestinal lymph before and after colchicine treatment. There was a 4-fold increase of the enzyme activity in lymph 3 h after treatment. The lymph flow rate, protein concentration and composition as measured by polyacrylamide gel electrophoresis were not affected. The kinetic properties of lymph sialyltransferase (protein and time dependence, pH optima and K m values for the substrate CMP-sialic acid) were essentially unchanged after treatment and were similar to the serum sialyltransferase. Alkaline phosphatase and lactic dehydrogenase activities were elevated in the lymph whereas maltase and lactase activities remained unchanged. Although intestinal lymph sialytransferase was increased by colchicine, enterectomy did not prevent the rise of serum sialyltransferase suggesting that the intestine is not a major source of the serum enzyme.