The Chemical Modification of the Lipase of Humicola lanuginosa by N-Bromosuccinimide in Urea Solution

Abstract

The chemical modifications of the lipase of Humicola lanuginosa by various reagents were investigated in the presence of urea. It was found that the lipase was completely inactivated by the addition of N-bromosuccinimide (NBS) in both the presence or absence of urea. According to the change of UV-spectra at 280nm and 260nm, it was confirmed that tryptophan residues of the Humicola lipase were specifically oxidized by N-bromourea which was produced by the reaction of NBS with urea. The lipase activity disappeared completely along with the oxidation of two of the three tryptophan residues in the lipase molecule.