Stabilized enzymes

Enzymes are stabilized by encagement in a double layer comprising a polyaldehyde base coat linked to the amino groups of the enzyme, and crosslinked therewith an outer polymer coat. The outer coat is made of a polymer which in the unlinked state comprises free amino and/or acyl hydrazide groups. Optionally the stabilized enzyme is immobilized within a matrix. There are described processes for the preparation of the encaged and optionally immobilized enzymes.