Abstract: Novel multi-component conjugates are provided having at least two components which are superoxide dismutase and catalase. Novel therapeutic agents utilising these conjugates are provided which are effective to reduce harmful levels of superoxide and hydroxyl free radicals in body tissues.

Abstract: The invention provides a conjugate comprising an enzyme having its antigenic sites or antigenicity masked by albumin and having a targeting agent attached, and a method for its preparation. The albumin is included in an amount sufficient to mask antigenicity of the enzyme. The targeting agent used has binding specificity for receptor sites on cells towards which it is desirable to direct the enzyme. Insulin, immunoglobulin G, antibody against human pancreatic tumor cell, and antibody against hyaluronic acid are exemplified as targeting agents.