Purification and characterisation of acetolactate decarboxylase from Leuconostoc lactis NCW1

A two-step strategy involving DEAE-cellulose and POROS PI anion exchange ch romatography has been developed for rapid purification of acetolactate deca rboxylase (ALD) from Leuconostoc lactis NCW1. This results in 5333-fold pur ification with a yield of 30%. Purified ALD is a dimer of 49-kDa subunits, has a pH optimum of 6.0, a pI of 4.2 and its activity is independent of met als or branched chain amino acids. At the optimum pH, the K-m for 2-acetola ctate (ALA) was found to be 1.3 mM and the turnover number was 4000 min(-1) . N-terminal sequence comparison with other ALDs showed little sequence con servation in this: region. Purified ALD does not catalyse: direct productio n of diacetyl from ALA, unlike the crude extract. (C) 2001 Federation of Eu ropean Microbiological Societies. Published by Elsevier Science B.V. All ri ghts reserved.