FEMS Microbiology Letters 5 (1979) 421-425 © Copyright Federation of European Microbiological Societies Published by Elsevier/North-Holland Biomedical Press 421 PURIFICATION AND PROPERTIES OF PYROCATECHUATE DECARBOXYLASE FROM ASPERGILL US NIGER A. RAMACHANDRAN, V. SUBRAMANIAN, M. SUGUMARAN and C.S. VAIDYANATHAN Department of Biochemistry, Indian Institute of Science, Bangalore-560 012, hzdia Received 28 February 1979 1. Introduction Non-oxidative decarboxylation of benzoic acid and its derivatives seems to occur in a variety of microorganisms. Table 1 lists the substrates, products and the microorganisms which effect such reactions [1 ]. Of the eleven decarboxylases listed, only three, viz. pyrocatechuate decarboxylase from Aspergillus niger [2], 6-methylsalicylate decarboxylase from Penicillium patulum [3], and 4,5-dihydroxyphtha- late decarboxylase from Pseudomonas testosteroni [4], have been purified and characterized. Interest- ingly, studies on these enzymes reveal the absence of any cofactors such as pyridoxal phosphate or thiamine pyrophosphate, the common cofactors of decarboxy- lation reactions. As a step towards the understanding of the mechanism of action of these decarboxylases, we intended to purify pyrocatechuate decarboxylase from A. niger and study some of its properties. In this communication, we wish to report a new affinity pro- cedure for the rapid purification of pyrocatechuate decarboxylase and some of the properties of the enzyme. TABLE 1 Decarboxylation of benzoic acid and its derivatives Substrate Product Organism Benzoic acid Benzene Salicylic acid Phenol 4-Hydroxybenzoic acid Phenol Pyrocatechuic acid Catechol 2,4-Dihydroxybenzoic acid Resorcinol Gentisic acid Quinol Protocatechuic acid Catechol 6-Methylsalicylicacid m-Cresol Orsellinic acid Orcinol 4,5-Dihydroxyphthalic acid Gallic acid Protocatechuic acid PyrogaUol Hypoxylum pruimatum Glomerella eingulata Klebsiella aerogenes (Aerobacter aerogenes) Glomerella cingulata Aspergillus niger Aspergillus nMulans Triehoderma lignorum Aspergillus nidulans Klebsiella aerogenes (Aerobacter aerogenes) AspergiUus Klebsiella aerogenes (Aerobaeter aerogenes) Rhodopseudomonas Penieillium patulum Glioeladium roseum Umbliearia pustulata Pseudomonas Klebsiella aerogenes (A erobaeter aerogenes)