The subtilisin complexes with dexamethasone and Alpha-2 macroglobulin were synthesized and were found to be immunoreactive to the specific antidexamethasone antibodies. These complexes also retain proteolytic activity when low molecular weight substrate was used by Homogeneous colorimetric method. The doubly labelled substrate was also used to study the enzyme activity in complex form. The Dex-subtilisin showed the proteolytic activity whereas Dex-subtilisin A2M did not show the proteolytic activity due to no access of small molecular weight substrate towards the large molecular weight protein in a co-complex form.