Synthesis of invertase (EC 22.214.171.124) in Pichia anomala is controlled by the carbon source in the culture medium. The enzyme was purified to homogeneity from P. anomala cells fully derepressed for invertase synthesis and shown to be a multimeric glycoprotein composed of identical subunits with an apparent molecular mass of 86.5 kDa. The carbohydrate moiety accounts for approx. 30% of the total mass of the molecule and consists of manno-oligosaccharides N-linked to the polypeptide. Most of the characteristics of the enzyme analysed in this study were similar to those previously reported for other yeast invertases, with the remarkable exception of its thermal sensitivity which appears after 15 min incubation at temperatures above 32 degrees C.