Physico-chemical and pharmacokinetic studies of avidin bioconjugates with thermosensitive polymers.

N-isopropilacrylamide-co-acrylamide 6000 Da with a LCST of 37°C, was activated and conjugated to avidin. Gel permeation analysis demonstrated that the polymer conjugation modifies remarkably the protein hydrodynamic volume. The bioconjugate displayed higher LCST compared to the original polymer. The polymer conjugation altered slightly the protein tertiary structure and the binding with both biotin and bionylated antibodies. Pharmacokinetic studies demonstrated that the bioconjugate shows longer permanence in the blood stream as compared to the native protein.