Refolding and characterisation of a heterologous expressed Phanerochaete chrysosporium cellobiohydrolase (CBHI.2)

Abstract

Cloned Phanerochaete chrysosporium ME446 cbhI.2 cDNA was successfully expressed in Escherichia coli as an insoluble, internal, biologically inactive protein. In vitro chemical refolding restored the activity of the crude CBHI.2. However, this enzyme was active against 4-methylumbelliferyl-ß-Dcellobioside
(MUC) and 4-methyllumbelliferyl-ß-D-lactopyranoside (MUL) substrates only. The crude enzyme lost almost 50% of its activity at 5 min at 100oC heat treatment whereas total inactivation was achieved at 30 min.