Subpicogram determination of oxytocin by an enzyme immunoassay using acetylcholinesterase as label.
The pure tetrameric form of Acetylcholinesterase (EC-3.1.1.7) from the electric eel electrophorus electricus has been covalently coupled to oxytocin. This conjugate has been used as tracer in a heterologous competitive immunoassay. Microtiter plates coated with a mouse monoclonal anti-rabbit immunoglobulin antibody were used to separate bound and free moieties of the tracer. Acetylcholinesterase activity bound to the solid phase was measured by a colorimetric assay. The minimum detectable concentration was 0.075 pg/well (ie 1.5 pg/ml) and precision was less than 8% at concentration above 0.15 pg/well. An extraction step improved sensitivity up to 10 times with good recoveries. To assess the validity of this assay, basal levels of oxytocin were measured during the oestrous cycle of a cow.
Marnet
P G
PG
INRA, Laboratoire de Recherches sur la Traite ENSAR, Rennes.
Volland
H
H
Pradelles
P
P
Grassi
J
J
Beaufils
M
M
D000110:Acetylcholinesterase; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003429:Cross Reactions; D005260:Female; D007106:Immune Sera; D007124:Immunoenzyme Techniques; D008969:Molecular Sequence Data; D010121:Oxytocin / Q000097:blood*; D011247:Pregnancy; D011817:Rabbits; D012756:Sheep
D007106:Immune Sera; D010121:Oxytocin; D000110:Acetylcholinesterase