EFFECT OF SOLVENTS AND OF TEMPERATURE ON THE OPTICAL ROTATORY PROPERTIES OF PEPSIN

Abstract

The optical rotation of pepsin was examined in the presence and absence of such reagents as urea, guanidine and LiBr in the wave length range from 350 to 700 m[mu]. Most determinations were made at 23[degree]C but the temperature was also varied from 15[degree] to 65[degree]C. Urea and guanidine salts do not affect the specific optical rotation, [a], at 600 m[mu]. A lowering of the rotary dispersion constant, [lambda], in most instances is indicative of the presence of low-molecular weight material that is a consequence of autodigestion of the enzyme. This constant also increases if the temperature is raised above 45[degree]C, and the change coincides with or precedes the inactivation of the protein.