Abstract: The antitope of an antibody is masked with a masking agent, followed by immobilization on a support. The masking agent is then eluted to produce an improved immunosorbent, which is capable of binding more than double the amount of an antigen than existing immunosorbents having the same antibody bound at the same density. Preferably, the masking agent is an antigen or other compound having an epitope for which the antitope of the bound antibody has an avidity. In a preferred embodiment, greater than 30% of the bound antibodies maintain the same vicinity as when unbound for specific antigen or hapten molecules. Preferably, the support is formed of any conventional immunosorbent support material which allows the bound and unbound antibody to maintain an avidity for the same compounds or antigens.

Abstract: A protein C activator is purified from the venom of the Southern copperhead snake. The resultant enzyme is a very specific and efficient activator of protein C. The high efficiency and specificity enables the sensitive measurement of functional protein C levels in plasma and other biological fluids. The enzyme is attached to a solid support material and the resultant enzyme reactor is capable of producing activated protein C at a high yield and is stable under the conditions of use.