SEPARATION OF PROTEOLYTIC AND ESTERASIC ACTIVITIES OF TRYPSIN BY REVERSIBLE STRUCTURAL MODIFICATIONS

A method of specifically and reversibly converting tryptophan to 1-formyltryptophan has been applied to bovine trypsin. The trypsin derivative shows only esterase activity, while the proteolytic activity can be restored after deformylation. On the average, at least three tryptophyl residues must be deformylated for recovering proteolytic activity. The effects of some non-aqueous solvents on the esterase and protease activities of trypsin are shown to be similar to those of formylation of the tryptophyl residues. It is concluded that the integrity of hydrophobic interactions within the enzyme molecule is not equally critical with respect to the two activities and that it is possible to operate a change in enzyme specificity by a controlled change in hydrophobic interactions. © 1969.