A novel method for enzyme immobilization was developed, which is based on the structural transition of the silk fibroin membrane from random coil or α-helix to β-sheet by using methanol, the enzyme was immobilized in the spaces formed by the intermolecular hydrogen bonds in the β-sheet conformation. The resulting urease electrode performs satisfactorily under appropriate operation conditions. It exhibits excellent thermal stability and over three months useful lifetime. In principle, this method should be applicable to immobilize other soluble enzymes which do not destroy the molecular structure of silk fibroin.

Key words: METHANOL, ENZYME ELECTRODES, RAMAN SPECTROMETRY, UREASE