Product Inhibition, Enzyme Inactivation, and Substrate Recalcitrance

Product Inhibition, Enzyme Inactivation, and Substrate Recalcitrance 

Cellulase is inhibited by its end products, cellobiose and glucose. For Trichoderma cellulase, the end product inhibition is uncompetitive, of the form  

Cellulase action can be inhibited or inactivated by several classes of compounds, including strong oxidants or reducing agents, metal ions, salts, solvents, and surfactants. The binding of the enzyme to cellulose can protect the enzyme from these compounds, so it is not easy to generalize the relationship between concentration and degree of inhibition (which is concentration dependent) or inactivation (which is time dependent). 

For most cellulosic materials, there is an upper limit to the degree of conversion that can be obtained. At this point, the accessibility of the remaining cellulose to the enzyme is limited, either by its pore structure or the presence of non-cellulosic components. The decrease in rate with increasing cellulose conversion is referred to as substrate recalcitrance . 

---