Arabinose transport

Physical or chemical modification of a substrate may additionally selectively affect transformation or uptake Keil and Kirchman (1992) compared the degradation of Rubisco uniformly labeled with 3H amino acids produced via in vitro translation to Rubisco that was reductively methylated with 3H-methane. Although both Rubisco preparations were hydrolyzed to lower molecular weights at approximately the same rate, little of the methylated protein was assimilated or respired. The presence of one substrate may also inhibit uptake of another, as has been demonstrated for anaerobic rumen bacteria. Transport and metabolism of the monosaccharides xylose and arabinose were strongly reduced in Ruminococcus albus in the presence of cellobiose (a disaccharide of glucose), likely because of repression of pentose utilization in the presence of the disaccharide. Glucose, in contrast, competitively inhibited xylose transport and showed noncompetitive inhibition of arabinose transport, likely because of inactivation of arabinose permease (Thurston et al., 1994). 

V. L-Arabinose Transport, Gene araE, and the Arabinose-Binding Protein 268... 

Direct Selection of Ara Mutants in the araC gene and esi Other Genes Affecting l-Arabinose Transport from araA Mutants... 

Inducibility allele (C" ), the wild-type allele, in which the isomerase, kinase, and epimerase and an L-arabinose transport system are inducible by L-arabinose. 

Pleiotropic constitutive allele (CO, in which the above enzymes and an L-arabinose transport system are produced constitutively—that is, in the absence of inducer. 

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