A UDP-sugar pyrophosphatase is developmentally regulated in the rat retina

MARTINA J.A.; DANIOTTI J.L.; MACCIONI H.J.F.

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 1995 vol. 64 p. 1274 - 1274

at retina tissue contains relatively high amounts of GD3 in relation to ganglio-series gangliosides even in the adult stages. This was attributed in part to an activity ratio between the enzyme that converts GM3 to GD3 [sialyltransferase II (ST-II)] and the enzyme that converts GM3 to GM2 [N-acetylgalactosaminyltransferase (GaINAc-T)] favorable to ST-II. Here we report the presence in the rat retina tissue of an activity that hydrolyzes one of the substrates of GaINAc-T, the donor sugar nucleotide UDP-GaINAc Chromatographic analyses of the products of degradation indicate that the activity corresponds to a UDP-sugar pyrophosphatase/phosphodiesterase I . The activity is developmentally regulated, increasing after day 4 of postnatal development to reach values -10-fold higher in the adult tissue . The activity sediments with the microsomal membranes, also hydrolyzes UDP-Gal, does not hydrolyze CMP-NeuNAc, requires Mn" , and does not require detergent. Kinetic data show