Transport of L-tryptophan in Saccharomyces cerevisiae
Language English Country United States Media print
Document type Journal Article
PubMed
2210491
DOI
10.1007/bf02820487
Knihovny.cz E-resources
- MeSH
- Biological Transport, Active drug effects MeSH
- Anaerobiosis MeSH
- Citrulline pharmacology MeSH
- Hydrogen-Ion Concentration MeSH
- Mutation MeSH
- Saccharomyces cerevisiae genetics metabolism MeSH
- Temperature MeSH
- Tryptophan metabolism MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Citrulline MeSH
- Tryptophan MeSH
In addition to the general amino acid transport system (GAP) of S. cerevisiae L-tryptophan is transported by another system with approximately 25% capacity of GAP, with a KT of 0.41 +/- 0.08 mmol/L and with a similar specificity as GAP (lower inhibition by Met, Pro, Ser, Thr and 2-aminoisobutyric acid; greater inhibition by Glu and His). The pH optimum of this system is at 5.0-5.5, activation energy above the transition point (20 degrees C) was 20 kJ/mol, below the transition point 55 kJ/mol. The transport by this system was virtually unidirectional, efflux amounting to at most 10% into a tryptophan-free medium. The transport itself was blocked by 2,4-dinitrophenol, antimycin A and uranyl nitrate. The system was synthesized de novo during preincubation with glucose = fructose greater than trehalose greater than ethanol within 30 min, and was degraded with a half-time of 15 min in the absence of further synthesis. The accumulation ratios of L-tryptophan in gap1 mutants were concentration-dependent (200:1 at 1 mumol L-Trp/L, 4:1 at 2.5 mmol L-Trp/L) and decreased with increasing suspension density from 200:1 to 5:1 (for 10 mumol L-Trp/L). The involvement of hydrogen ions in the uptake was clearly demonstrated by the effect of D2O even if it could not be established by either shifts of pHout or membrane depolarization.
See more in PubMed
Eur J Biochem. 1970 May 1;14(1):197-204 PubMed
Eur J Biochem. 1975 Nov 15;59(2):373-6 PubMed
Folia Microbiol (Praha). 1977;22(5):360-2 PubMed
J Bacteriol. 1970 Sep;103(3):770-7 PubMed
Biochim Biophys Acta. 1982 Sep 27;698(3):243-51 PubMed
Biochim Biophys Acta. 1986 Dec 22;864(3-4):223-56 PubMed
Biochim Biophys Acta. 1977 Nov 1;470(3):484-91 PubMed
J Gen Microbiol. 1947 Jan;1(1):86-90 PubMed
Biochim Biophys Acta. 1972 Nov 2;288(2):380-9 PubMed
J Theor Biol. 1976 Apr;57(2):313-29 PubMed
Folia Microbiol (Praha). 1988;33(4):281-4 PubMed
Folia Microbiol (Praha). 1988;33(4):285-91 PubMed
FEBS Lett. 1982 Apr 5;140(1):22-6 PubMed
FEBS Lett. 1990 May 21;264(2):203-5 PubMed
Ann Inst Pasteur (Paris). 1958 Jul;95(1):73-87 PubMed
