[Stabilization of polyacrylamide gel immobilized horseradish peroxidase by its covalent coupling to albumin].

Pretreatment of peroxidase by its covalent coupling to inert proteins and albumin by means of glutaraldehyde considerably increases the thermostability and specific activity of polyacrylamide gel (PAAG) immobilized peroxidase. The effects of PAAG composition on the catalytic properties of the immobilized oligomers: peroxidase-inert proteins-albumin, are studied. The oligomers immobilized in 40% PAAG (10% N,N'-methylenebisacrylamide) possess the maximal specific activity (4.5 nmol/g). The effects of oligomer composition on their catalytic activity and stability in PAAG are studied. The stability of oligomers of optimal composition (ratio of albumin/peroxidase is 2.4), incorporated into 40% PAAG, is 15 times higher as compared to that of the soluble enzyme and 250 times higher as compared to that of the enzyme incorporated into PAAG without pretreatment. A mechanism of stabilizing effect exerted by albumin on peroxidase in PAAG-immobilized oligomers, is discussed.