Denervation alterations in surface membrane glycoprotein glycosyltransferases of mammalian skeletal muscle

Plasma membrane fractions isolated from rat skeletal muscle demonstrate an increased carbohydrate composition after 7 days of denervation. Total hexose content increased 3.5-fold (from 278 to 985 nmol/mg protein), hexosamine increased 1.7-fold (from 30 to 52 nmol/mg protein), and sialic acid increased 2.5-fold (from 17 to 43 nmol/mg protein). The cytidine monophosphate (CMP) sialic acid-sialyl transferase and uridine diphosphate (UDP) galactose-galactosyl transferase activities localized in the enriched skeletal muscle plasma membrane fraction were also found to increase with denervation. Sialyl transferase activity increased from 27 to 50 pmol sialic acid transferred/mg protein/h using the acceptor asialo-fetuin. The galactosyl transferase activity increased from 21 to 44 pmol galactose transferred/mg protein/h using the acceptor asialo-agalacto-fetuin. These alterations in composition and transferase activities may help explain the renewed capacity for cell-cell interactions associated with denervation.