Oxidation of peptides and proteins by Trichoderma reesei and Agaricus bisporus tyrosinases.

摘要

Protein oxidation and cross-linking capacity of a novel tyrosinase from Trichoderma reesei (TrTyr) was compared with that of a well-characterized tyrosinase from Agaricus bisporus (AbTyr). Tests were performed using a range of proteins ( beta-casein, BSA, wool fibres and GYG and EGVYVHPV peptides) and analytical techniques (O2 consumption measurement, SDS-PAGE, RP-HPLC, MALDI-TOF-MS and fluorescence microscopy). Results indicated that TrTyr was more efficient at cross-linking peptides and proteins than AbTyr, but that protein size and structure governed TrTyr activity. Hence, beta-casein, which has a random coil structure, was cross-linked by TrTyr in 3 h, whilst BSA, which is large and compact, was not cross-linked even after 24 h. It is concluded that TrTyr is a potential tool for protein cross-linking and/or modification.