ISSN:
1573-0972
Keywords:
Candida utilis
;
inhibition
;
kinetics
;
regulation
;
sugar
;
transport
;
xylose
;
yeast
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract Low-affinity (K m=67.6±3.2 mM) and high-affinity (K m=1.9±1.2 mM) D-xylose transport occur in Candida utilis grown, respectively, on D-glucose or D-xylose. Starvation of glucose-grown cells decreases the K m value (10.5±2.6 mm). The high-affinity system appearing during starvation required protein synthesis and it was inactivated when cells were exposed to glucose, by a process independent of protein synthesis. High-affinity transport was accompanied by transient alkalinization of yeast suspensions, indicating that it is a proton symport, whereas low-affinity transport was not. Both systems, however, were inhibited by metabolic inhibitors and by replacing H2O in the transport assay with D2O, indicating that both may be proton symports. Glucose and acetic acid also inhibited both high-and low-affinity xylose transport.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00383080
