Energy Requirement for l-Glutamate Uptake and Utilization by Hansenula subpelliculosa Cells

AUTOR(ES)

Shieh, K. Z.

RESUMO

Shieh, K. Z. (Illinois Institute of Technology, Chicago), and L. R. Hedrick. Energy requirement for l-glutamate uptake and utilization by Hansenula subpelliculosa cells. J. Bacteriol. 92:1638–1644. 1966.—Cells of the yeast Hansenula subpelliculosa require an energy source for the uptake of glutamate. A lag period of 20 to 40 min was required after the addition of glucose to the cells before glutamate uptake was initiated. When cells were preincubated in glucose, and washed with distilled water prior to the addition of glutamate, there was no lag period. Preincubation in glucose and glutamate lowered both the rate and the total uptake of glutamate as compared with cells preincubated in glucose alone. This is attributed to the partial utilization of the glucose-metabolite by glutamate or to the partial saturation of binding sites by glutamate during the preincubation period. Transport of glutamate by these yeast cells appears to be via a carrier, where energy is required for the binding of the amino acid to nonspecific binding sites. In addition to total uptake, some aspects of the C14-glutamate utilization were measured. Of the total uptake, 58% was metabolized and converted to CO2, 25.2% remained in the soluble pool, and 16.8% was incorporated into trichloroacetic acid-insoluble products. When the available energy source was depleted, the processes of uptake, metabolism, and incorporation ceased, even though there was an ample supply of glutamate present within the cells. Removal of cells from glutamate and addition of glucose reinitiated the incorporation of glutamate into proteins and other trichloroacetic acid-insoluble compounds. Therefore, an additional energy source is required with this species of yeast for glutamate uptake, for the priming of mechanisms required for its metabolism, and for its incorporation.

Documentos Relacionados

• Brain L-glutamate decarboxylase: purification and subunit structure.
• Postsynaptic activation at the squid giant synapse by photolytic release of L-glutamate from a 'caged' L-glutamate.
• Inhibition of L-glutamate and GABA synaptosome uptake by crotoxin, the major neurotoxin from Crotalus durissus terrificus venom
• Carp horizontal cells in culture respond selectively to L-glutamate and its agonists.
• Permeability changes induced by L-glutamate at the crayfish neuromuscular junction.