amylose but also aminopectine chitosan dextran agarose etc are employed sugars having carboxyl groups are undesirable to use in the present process since they cause intermolecular crosslinking of proteins with one another when pharmaceuticals of enzyme proteins are administered in a base form the half life period is so short that they are rapidly excreted from the kidney or decomposed so that the drug efficacy often cannot be obtained the present invention is applied to achieving such increase in the stability of enzyme proteins in blood an increase in the retention time thereof in blood etc in example described later there will be described an increase in the retention time in blood of superoxide dismutase hereinafter abbreviated to sod which is an enzyme specifically decomposing the superoxide anion of active enzymes and having recently come to be used for removal of blood vessel obstacles in the brain and heart behcet 39 s disease etc the present invention will be described in more detail by way of examples but it should not be construed to be limited thereto amylose weight average molecular weight 29 000 1 0 g was dissolved in a 0 1 m phosphoric acid buffer ph 8 5 10 ml followed by adding glycylglycine in a quantity by mol of 5 times that of amylose and scbh in a quantity by mol of 50 times that of amylose agitating the mixture at 80 u00b0 c for 2 days adjusting the ph to 3 with conc hydrochloric acid.