Open AccessThe monoclonal antibody 2G8 is carbohydrate‐specific and distinguishes between different forms of vertebrate cholinesterases
Author(s) -
LIAO Jian,
HEIDER Harald,
SUN ManChi,
STIEGER Susi,
BRODBECK Urs
Publication year - 1991
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1991.tb15986.x
Subject(s) - electrophorus , torpedo , epitope , chemistry , monoclonal antibody , acetylcholinesterase , butyrylcholinesterase , biochemistry , enzyme , polyclonal antibodies , microbiology and biotechnology , antibody , biology , aché , acetylcholine receptor , receptor , immunology
The monoclonal antibody (mAb) 2G8 (subclass IgG 2a ) raised against acetylcholinesterase (AChE, EC 3.1.1.7) from electric organ of Torpedo nacline timilei crossreacted with AChE from Torpedo marmorata , electric eel ( Electrophorus electricus ), flounder ( Platichthys flesus ) body muscle, rat brain, bovine brain, and human brain, this suggests that the epitope to which mAb 2G8 bound had been highly conserved during evolution. No crossreaction was found with AChE from human and bovine erythrocytes, nor with butyrylcholinesterase (BtChE, EC 3.1.1.8) from human serum. Binding of mAb 2G8 to the globular G 2 form of AChE from T. marmorata strongly decreased enzyme activity, while no significant inhibition was found with either collagen‐tailed, asymmetric forms, or with the enzymes from flounder body muscle or mammalian sources. The possibility that mAb 2G8 bound to anionic sites of AChE could be excluded since neither edrophonium chloride nor decamethonium bromide influenced the binding of 2G8 to the enzymes. Enzyme‐linked immunosorbent assay and Western blot showed that heat‐denatured, diisopropylfluorophosphate‐treated, CNBr‐ and trypsin‐digested AChE from T. marmorata still reacted with mAb 2G8; this indicates that the epitope to which 2G8 bound, at least partially, belonged to a continuous determinant. Treatment of cholinesterases with N ‐glycosidase F abolished crossreaction with 2G8, showing that an essential part of the epitope consisted of N‐linked carbohydrates.