Human plasma and serum trypsin-like esterase activity.

A spectrophotometric method using benzoyl arginine ethyl ester (BAEE) is described for the assay of serum and plasma trypsin-like esterase activity. The method was used to find activities in serum and plasma (anticoagulated with oxalate and heparin) from 12 healthy males at 3 different reaction pH’s. The effects of calcium, oxalate, heparin, soybean trypsin inhibitor, ovomucoid, and heat on this activity were also measured. Values of esterase activity were significantly different, indicating a variable enzyme or inhibitor composition in the 3 sets of samples. Plasma from heparinized blood gave unique activity responses to pH and to the agents tested for effect.