Endoglycosidase H susceptibility of secreted and intracellular forms of dopamine beta-hydroxylase
Sabban, E.L.; McMahon, A.; Kuhn, L.J.
Biochemistry International 19(4): 769-775
1989
ISSN/ISBN: 0158-5231 PMID: 2515859 Document Number: 335319
In an attempt to characterize the differences between various forms of dopamine beta-hydroxylase (DBH) the endoglycosidase H (endo H) susceptibilities of the intracellular and secreted DBH were compared. Both soluble and membrane-bound forms of newly synthesized DBH in PC12 cells were found to be susceptible to endo H. Soluble DBH, apparent Mr of 73K, was converted to 67K Mr and membrane-bound DBH, apparent Mr of 77K and 73K, shifted to 69K and 67K. Upon stimulation with the potent secretagogue, BaCl2, over 65% of intracellular dopamine and norepinephrine were secreted together with the soluble proteins of the secretory granules. DBH, released upon this stimulated secretion, was relatively resistant to endo H compared to the intracellular forms.