Identification of an endogenous inhibitor of the UDP-N-acetylgalactosamine:GM3, N-acetylgalactosa- minyl transferase as Apolipoprotein AI.

CONDE CB; GRABOIS VR; DEZA SB; CAPUTTO BL

SPRINGER/PLENUM PUBLISHERS

Lugar: New York; Año: 1997 vol. 22 p. 483 - 483

previously described inhibitor of the UDP-N-acetylgalactosamine: GM3, N-acetylgalactosaminyltransferase (GalNAc-T) (Quiroga et al., 1, 2), was purified from chicken blood serum by a new procedure. When subjected to SDS-PAGE, two major polypeptides of 27 and 70 kDa were observed. When tested in vitro, only the 27 kDa polypeptide inhibited the GalNAc-T. When added to chick cerebral embryonic neurons in culture, both polypeptides inhibited neuritogenesis. Both the 27 kDa and the 70 kDa fractions were present in the cells at 3 h following their addition to the cultures; both polypeptides had aneuritogenic activity and both inhibited the incorporation of [3H]-galactose into the cell gangliosides modifying their labeling pattern to a similar extent. Sequencing of the amino terminal end of the polypeptides showed that 18 and 9 amino acids from, respectively, the 27 and the 70 kDa polypeptides, were 100% homologues with the corresponding region of chick apolipoprotein Al (apo Al). After addi