Crystallization and preliminary X-ray diffraction studies of human salivary α-amylase

Nonglycosylated α‐amylase, a major component of human parotid saliva, has been crystallized by the vapor diffusion technique using 2‐methyl‐2,4‐pentanediol as the precipitant in the presence of CaCl2 at pH 9.0. The crystals are orthorhombic, space group P212121 with unit cell dimensions of a = 53.3, b = 75.8, and c = 138.1 Å. The asymmetric unit contains one amylase molecule. The solvent content is 54%. The crystals are stable to X‐rays and diffract up to 2.8 Å and appear to be suitable for X‐ray diffraction studies.