Low-affinity, high-capacity system of glucose transport in the ruminal bacterium Streptococcus bovis: evidence for a mechanism of facilitated diffusion.
AUTOR(ES)
Russell, J B
RESUMO
The glucose phosphotransferase system (PTS) of Streptococcus bovis could not account for the glucose consumption of exponential cultures, and the kinetics of glucose transport were biphasic. A PTS-deficient mutant lost the high-affinity, low-capacity system but retained its ability to take up glucose at high substrate concentrations. The low-affinity, high-capacity system did not require a proton motive force or ATP and could not be driven by an artificial membrane potential in the presence or absence of sodium. Since low-affinity transport was directly proportional to the external substrate concentration and exhibited counterflow kinetics, it appeared that a facilitated-diffusion mechanism was responsible for glucose transport at high substrate concentrations.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=184946Documentos Relacionados
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