Properties of the 3-o-methyl-D-glucose transport system in Acholeplasma laidlawii.

AUTOR(ES)

Tarshis, M A

RESUMO

Transport of 3-O-methyl-D-glucose (3-O-MG) by Acholeplasma laidlawii cells was studied. The 3-O-MG transport system appeared to be constitutive in cells grown on 3-O-MG and glucose; the transport process depended on the concentration of substrate used and exhibited typical saturation kinetics, with an apparent Km of 4.6 muM. 3-O-MG was transported as a free carbohydrate and was not metabolized further in the cell. Dependence on pH and temperature and the results of efflux and "counterflow" experiments demonstrated the carrier nature of the transport system. 6-Deoxyglucose and glucose competitively inhibited 3-O-MG transport, whereas maltose inhibited in non-competitively. p-Chloromercuribenzoate, p-chloromercuribenzene sulfonate, N-ethylmaleimide, and iodoacetate inhibited transport of 3-O-MG. Cells were able to accumulate 3-O-MG against a concentration gradient. Some electron transfer inhibitors (rotenone and amytal), arsenate, dicyclohexylcarbodiimide, and proton conductors such as 2,4-dinitrophenol, carbonylcyanide, m-chlorophenylhydrazone, pentachlorophenol, and tetrachlorotrifluoromethylbenzimidazole inhibited this process.

Documentos Relacionados

• Estimation of 3-O-methyl-D-glucose in the presence of glucose.
• Immunological properties of glycolipids from membranes of Acholeplasma laidlawii.
• Acylated proteins in Acholeplasma laidlawii.
• Adenylate energy charge in Acholeplasma laidlawii.
• Presence of protein constituents of the gram-positive bacterial phosphotransferase regulatory system in Acholeplasma laidlawii.