Nucleation and Morphology of Chymotrypsinogen Crystals

Abstract

IT has been suggested recently¹ that the morphology of enzyme crystals grown from solutions at various super-saturations² may be interpreted in terms of the basic mechanisms of nucleation. Little is known of either the nucleation mechanism or the solid-state properties of enzymes, since most are notoriously unstable even under mild conditions. The work presented here is a preliminary examination of the nucleation of bovine α-chymotrypsino-gen from solution. This enzyme has been selected because it is available commercially in a particularly pure form and something is known of its solid-state structure. From X-ray diffraction data³ the molecule is said to be spherical with a radius of 21 Å. It consists of approximately 246 amino-acid units⁴ and has a molecular volume of 17,100 ml./mole⁵.