The catalytic rate constant ofTrichoderma longibrachiatumfamily 7 cellobiohydrolase on cellulose

Abstract

AbstractCellobiohydrolases are considered ‘workhorse’ cellulases in the saccharification of cellulosic substrates. As solubilized cellobiose products are easily measured, cellobiohydrolases have been useful tools in studies of cellulose hydrolysis. Access to purified cellobiohydrolases with known catalytic rate constant (kcat), or the turnover rate, is particularly useful. Here, we determined the kcatof the commercially availableTrichoderma longibrachiatumCBHI at 30°C, 40°C, and 50°C to be 0.5 s-1, and 2.6 s-1, and 5.3 s-1, respectively. The energy of activation of productively boundTlCBHI was estimated to be 93 ± 17 kJ/mol.