Crystallization and preliminary crystallographic data of purple acid phosphatase from red kidney bean

Purple acid phosphatase from red kidney bean has been crystallized from ammonium sulfate solutions in the pH range from 3·5 to 5·5. The crystal form is tetragonal bipyramidal and the largest crystals grew up to 2·0 mm long. Systematic absences indicate one of the enantiomorphic space groups P41212 (92) or P43212 (96) with cell dimensions a = b = 104·1(1)Åandc = 308·7(2)Å. The asymmetric unit contains one dimer with Mr of 110,700, determined by ultraviolet-laser desorption mass spectrometry. The crystals, with a salt-free density of 1·12 g/cm3 and a water content of 67%, diffract to 3·5 Å