Uptake of phenol by Trichosporon cutaneum.
AUTOR(ES)
Mörtberg, M
RESUMO
The soil yeast Trichosporon cutaneum, which is distinguished by having a strictly oxidative metabolism, can be induced to utilize phenol as a sole carbon source. The present paper shows that such phenol-induced cells contain a specific, energy-dependent uptake system for phenol. Phenol uptake is not directly linked to its o-hydroxylation inside the cell, the first step of phenol metabolism. The Km for uptake is 235 +/- 30 microM, that for hydroxylation only 4.5 +/- 0.5 microM. Further, the phenol analog 2,6-dimethylphenol, which can not be hydroxylated, competes with phenol for the uptake system. The pH dependence of uptake indicates that phenolate is an essential form during the uptake process. The energy requirement for phenol uptake is indicated by effects of various inhibitors of energy generation, including proton-conducting uncouplers. Direct monitoring of proton movements in a pH-stat during phenol uptake indicates a phenol-proton symport. One proton is cotransported with every phenol molecule. Phenol competes with the uptake of sucrose and glycerol by cells grown on these substrates. Under such conditions the uptake of phenol seems to proceed through a different system, with lower affinity for phenol than in phenol-grown cells.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=214927Documentos Relacionados
- Induction of high-affinity phenol uptake in glycerol-grown Trichosporon cutaneum.
- Metabolism of phenol and resorcinol in Trichosporon cutaneum.
- Transport and hydrolysis of disaccharides by Trichosporon cutaneum.
- Degradation of 4-hydroxyphenylacetic acid by Trichosporon cutaneum.
- Postoperative endophthalmitis due to Trichosporon cutaneum.
