Reagents for the preparation of chromophorically labeled polyethylene glycol-protein conjugates.
We have developed a new class of reagents (2) for the covalent attachment of polyethylene glycol to proteins. These reagents (2) are the monomethoxypolyethylene glycol esters of 4-fluoro-3-nitrobenzoic acid. The reaction of 2 with lysine epsilon-amino groups produces a chromophore which can be used to quantitate the polyethylene glycol to protein molar ratio. Bovine (Zn, Cu) superoxide dismutase was used as a model protein for conjugation with 2. When monomethoxypolyethylene glycol of average molecular weight 2105 was used, a conjugate was obtained with a polyethylene glycol to protein molar ratio of 8.88 retaining 100% of native enzymatic activity; monomethoxypolyethylene glycol of average molecular weight 5210 yielded a conjugate with a polyethylene glycol to protein molar ratio of 9.96 retaining 73% of native enzymatic activity.
Medicinal Chemistry Department, Sterling Winthrop Pharmaceuticals Research Division, Sterling Winthrop Inc., Malvern, Pennsylvania 19355.
D L
DL
Ladd
R A
RA
Snow
D000818:Animals; D002417:Cattle; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002863:Chromogenic Compounds; D009579:Nitrobenzoates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D013053:Spectrophotometry; D013482:Superoxide Dismutase / Q000032:analysis / Q000737:chemistry; D014302:Trinitrobenzenesulfonic Acid / Q000737:chemistry
D002863:Chromogenic Compounds; D009579:Nitrobenzoates; D011506:Proteins; D011092:Polyethylene Glycols; C081549:4-fluoro-3-nitrobenzoic acid; D014302:Trinitrobenzenesulfonic Acid; C028210:monomethoxypolyethylene glycol; D013482:Superoxide Dismutase