Sialyltransferases in Young Rat Brain
Brain sialyltransferases catalize the transfer of sialic acid (NeuNAc) from CMP-NeuNAc to glycoprotein and glycolipid acceptors. In this study sialyltransferase activities were simultaneously examined utilizing both endogenous and exogenous glycoprotein and glycolipid acceptors. The assumptions were made that the activities obtained with exogenously added substrates are a measure of the amount of sialyltransferases present and that the endogenous activities give additional information on the identity of the endogenous glycoprotein and glycolipid acceptors. Unless otherwise indicated, experiments were performed with a total particulate preparation obtained by centrifuging the homogenate of 11–15 day rat cerebra at 105,000 x g for 1 hr. Four types of sialyltransferase reactions were investigated (A, B, C and D below). Each were assayed by measuring the incorporation (14C)NeuNAc from (14C)-CMP-NeuNAc into a glycolipid or glycoprotein acceptor (NG & DAIN, 1977a,b). The abbreviations for individual gangliosides are those proposed by SVENNERHOLM (1964).
KeywordsSialic Acid Chicken Brain Heat Pretreatment Sialyltransferase Activity Sucrose Gradient Fraction
Unable to display preview. Download preview PDF.
- KAUFMAN B., BASU S. & ROSEMAN S. (1968): Enzymatic synthesis of disialogangliosides from monosialogangliosides by sialyltransferases from embryonic chicken brain. J. Biol. Chem. 243, 5804–5807.Google Scholar
- MESTRALLET M., CUMAR F.A. & CAPUTTO R. (1977): Trisialoganglioside synthesis by a chicken brain sialyltransferase. Comparative study with the similar reaction for the synthesis of disialoganglioside. Mol. Cell. Biochem. 16, 63–70.Google Scholar
- SCHACHTER H. & RODEN L. (1973): The biosyntheis of animal glycoproteins, in “Metabolic Conjugation and Metabolic Hydrolysis”, FISHMAN W.H., Eds., Vol. 3, Academic Press (New York and London), pp. 2–149.Google Scholar