Glucose transport in isolated prosthecae of Asticcacaulis biprosthecum.
Active transport of glucose in prosthecae isolated from cells of Asticcacaulis biprosthecum was stimulated by the non-physiological electron donor N, N, N', N'-tetramethyl-p-phenylenediamine dihydrochloride. Glucose uptake was mediated by two transport systems; the apparent Km of the high-affinity system was 1.8 muM and that of the low-affinity system was 34 muM. Free glucose accumulated within prosthecae at a concentration 60 to 200 times above that present externally, depending on the Km of the system being observed. The glucose transport system in prosthecae was stereospecific for D-glucose, and neither methyl alpha-D-glucopyranoside nor 2-deoxyglucose was transported. Uptake of glucose was inhibited by N-ethylmaleimide (NEM) and p-chloromercuribenzoate (PCMB), and the inhibition by PCMB but not by NEM was reversed by dithiothreitol. Glucose uptake was also inhibited by the uncoupling agents 5-chloro-3-t-butyl-2'-nitrosalicylanilide (S-13), 5-chloro-3-(p-chlorophenyl)-4'-chlorosalicylanilide (S-6), and carbonyl-cyanide m-chlorophenylhydrazone (CCCP) and by the respiratory inhibitor KCN. Efflux of glucose from preloaded prosthecae was induced by PCMB and KCN, but not by S-13 or CCCP. Glucose uptake was not affected by arsenate or an inhibitor of membrane-bound adenosine triphosphatases, N, N'-dicyclohexylcarbodiimide. The lack of inhibition by these two compounds, combined with the extremely low levels of adenosine 5'-triphosphate present in prosthecae, indicates that adenosine 5'-triphosphate is not involved in the transport of glucose by prosthecae.
D000255:Adenosine Triphosphate / Q000378:metabolism; D001149:Arsenates / Q000494:pharmacology; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D001693:Biological Transport, Active / Q000187:drug effects; D002729:Chloromercuribenzoates / Q000494:pharmacology; D003486:Cyanides / Q000494:pharmacology; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D005947:Glucose / Q000031:analogs & derivatives / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009005:Monosaccharides / Q000378:metabolism; D013237:Stereoisomerism; D013696:Temperature; D013772:Tetramethylphenylenediamine / Q000494:pharmacology; D014475:Uncoupling Agents / Q000494:pharmacology
D001149:Arsenates; D002729:Chloromercuribenzoates; D003486:Cyanides; D009005:Monosaccharides; D014475:Uncoupling Agents; D004024:Dicyclohexylcarbodiimide; D000255:Adenosine Triphosphate; D005947:Glucose; D005033:Ethylmaleimide; D013772:Tetramethylphenylenediamine; D004229:Dithiothreitol