Keywords: PVA; polyvinyl alcohol; OPA; oxidized PVA; OPH; OPA hydrolase; pNP; p-nitrophenyl; pNPA; pNP acetate; pNPB; pNP butyrate; pNPC; pNP caprylate; pNPL; pNP laurate; pNPP; pNP palmitate; DMSO; dimethyl sulfoxide; PEG; polyethylene glycol; DTT; dithiothreitol;