The advantages associated with the described immobilized enzyme reactor include: (1) Use of the common rate equations and kinetic parameters. (2) Detection of significant lag periods. (3) Quantitative measure for non-covalently attached enzyme. (4) The means for washing the immobilized enzyme allows for the repeated use of the same matrix-bound enzyme. (5) Constant temperature control. (6) Both unbound native and matrix-bound enzyme may be reacted under identical conditions. (7) No grinding of the glass-bound enzyme or other matrix fragmentation occurs because no abrasive forces are required for stirring.