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.