Comparison of 4-hydroxynzoate decarboxylase and phenol carboxylase activities in cell-free extracts of a defined, 4-hydroxybenzoate and phenol-degrading anaerobic consortium
✍ Scribed by Claudia Gallert; Josef Winter
- Publisher
- Springer
- Year
- 1992
- Tongue
- English
- Weight
- 553 KB
- Volume
- 37
- Category
- Article
- ISSN
- 1432-0614
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✦ Synopsis
Two 4-hydroxybenzoate decarboxylase activities and a phenol carboxylase activity were found in cell-free extracts of a defined, 4-hydroxybenzoate-or phenol-grown consortium. Both decarboxylase activities were loosely membrane-associated and required K ÷ but a different pH and ion strength. Loss of activity of both decarboxylases by EDTA could be compensated by Zn z+ ions. The K m values for 4-hydroxybenzoate and K ÷ of the decarboxylase activities with pH optima at 6.4 or 7.8 were 0.02 and 2.5 or 0.004 and 0.5 mM, respectively. 3,4-Dihydroxybenzoate, 3,4,5-trihydroxybenzoate, 3,5-dimethoxy-4-hydroxybenzoate and 3-chloro-4-hydroxybenzoate were also decarboxylated by both enzyme activities. The phenol carboxylase was a soluble enzyme with its pH optimum at 6.5. It required K +, Rb + or NH~-as monovalent, Zn 2+, Mg 2+, Mn 2+ or Ni 2+ as divalent cations and catalysed the carboxylation of phenol if 2,4-, 2,3,4-or 2,4,6-hydroxybenzoates were absent. The three enzyme activities were not influenced by Avidin and thus were probably not biotin-dependent enzymes.