Poly-ε-lysine amylase conjugates to increase the stability of enzyme

Poly-ε-lysine (ε-PL), an unusual naturally occurring homopolyamide of L-lysine having linkage between ε-amino and α-carboxyl groups, is biodegradable, edible and non-toxic towards human and environment. The conjugate of ε-PL with amylase was successfully prepared by ionic interaction. The ε-PL-amylase conjugate showed better temperature and pH stability than native enzyme. The degradation of enzyme by temperature and pH followed first order degradation kinetics. The k value (reaction constant), D value (decimal reduction time) and activation energy confirmed the better temperature stability of conjugated enzymes than native enzyme. The k_m and V_max values were found to be similar for both conjugated and native enzyme suggesting, no change in enzyme configuration which alters the substrate binding.