RESUMEN
Oenococcus oeni has numerous amino acid requirements for growth and dipeptides could be important for its nutrition. In this paper the individual or combined effect of dipeptides on growth of O. oeni X2L in synthetic media deficient in one or more amino acids with L-malic acid was investigated. Utilization of dipeptides, glucose, and L-malic acid was also analyzed. Dipeptides were constituted by at least one essential amino acid for growth. Dipeptides containing two essential amino acids, except leucine, had a more favorable effect than free amino acids on the growth rate. Gly-Gly was consumed to a greater extent than Leu-Leu and a rapid exodus of glycine to the extracellular medium accompanied it. The microorganism could use glycine in exchange for other essential amino acids outside the cell, favoring growth. In the presence of Leu-Leu, the increase in glucose consumption rate could be related to the additional energy required for dipeptide uptake.
Asunto(s)
Dipéptidos/farmacología , Cocos Grampositivos/efectos de los fármacos , Cocos Grampositivos/crecimiento & desarrollo , Aminoácidos/metabolismo , Medios de Cultivo/química , Dipéptidos/metabolismo , Glucosa/metabolismo , Glicilglicina/metabolismo , Glicilglicina/farmacología , Cocos Grampositivos/metabolismo , Cinética , Malatos/metabolismoRESUMEN
We have studied the metabolism of diglycine and triglycine in the isolated non-filtering rat kidney. Kidneys from adult male Wistar Kyoto rats weighing 250-350 g were perfused with Krebs-Henseleit solution containing either 1 mM diglycine or triglycine. The analysis of the peptide residues and their components was performed using an amino acid microanalyzer utilizing ion exchange chromatography. Diglycine was degraded to a final concentration of 0.09 mM after 120 min (91%); this degradation occurred predominantly during the first hour, with a 56% reduction of the initial concentration. The metabolism of triglycine occurred similarly, with a final concentration of 0.18 mM (82%); during the first hour there was a 67% reduction of the initial concentration of the tripeptide. Both peptides produced glycine in increasing concentrations, but there was a slightly lower recovery of glycine, suggesting its utilization by the kidney as fuel. The hydrolysis of triglycine also produced diglycine, which was also hydrolyzed to glycine. The results of the present study show the existence of functional endothelial or contraluminal membrane peptidases which may be important during parenteral nutrition.
Asunto(s)
Glicilglicina/metabolismo , Oligopéptidos/metabolismo , Insuficiencia Renal/metabolismo , Animales , Masculino , Ratas , Ratas WistarRESUMEN
Renal metabolism of Glycyl-glycine (Gly-gly), Glycyl-proline (Gly-pro) and Prolyl-glycine (Pro-gly) was studied in the non-filtering, isolated perfused rat kidney. Gly-gly is metabolized by more than 90% after 120 min of perfusion. Gly-pro is more resistant to degradation and about 75% of the original peptide can be found intact in the perfusate at the end of perfusion. For Pro-gly, only 25% remains intact at the end of the experiment. Glycine was also monitored as another marker for dipeptide degradation and its production increased throughout the perfusion time. In some experiments we also determined the production of proline. We conclude from these experiments that the basolateral membrane, or perhaps the kidney blood vessels, possess an efficient apparatus for the hydrolysis of Gly-gly and Pro-gly. This mechanism is less efficient in the case of Gly-pro. This confirms an earlier hypothesis that dipeptide metabolism does not occur solely in the brush-border membranes.
Asunto(s)
Dipéptidos/metabolismo , Glicilglicina/metabolismo , Riñón/metabolismo , Animales , Riñón/fisiología , Masculino , Perfusión , Ratas , Ratas EndogámicasRESUMEN
Rehal metabolism of Glycyl-glycine (Gly-gly), Glycyl-proline (Gly-pro) and Prolyl-glycine (Pro-gly) was studied in the non-filtering, isolated perfused rat kidney. Gly-gly is metabolized by more than 90% after 120 min of perfusion. Gly-pro is more resistant to degradation and about 75% of the original peptide can be found intact in the perfusate at the end of perfusion. For Pro-gly only 25% reamins intact at the end of the experiment. Glycine was also monitored as another marker for dipepptide degratation and ins production increased throughout the perfusion time. In some experiments we also determined the production of proline. We conclude from these experiments that the basolateral membrane, or perhaps the kidney blood vessels, posses an efficient apparatus for the hydrolysis of Gly-gly and Pro-gly. This mechanism is less efficient in the case of Gly-pro. This confirms an earlier hypothesis that dipeptide metabolism does not occur solely in the brush-border membranes