These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Transamination of neutral amino acids and 2-keto acids in pancreatic B-cell mitochondria.
    Author: Lenzen S, Schmidt W, Panten U.
    Journal: J Biol Chem; 1985 Oct 15; 260(23):12629-34. PubMed ID: 2864344.
    Abstract:
    High aminotransferase activities catalyzing the reactions between L-glutamate and L-glutamine and the aliphatic ketomonocarboxylic acids 2-ketoisocaproate, 2-ketocaproate, and 2-ketoisovalerate were observed in pancreatic B-cell mitochondria. While maximal rates of transamination with L-glutamate were observed in the presence of micromolar concentrations of keto acid, maximal rates of transamination with L-glutamine were recorded only in the presence of millimolar concentrations of keto acid. The insulin secretagogue 2-ketoisocaproate was the most effective transamination partner for L-glutamate, while the insulin secretagogue 2-ketocaproate was the most effective transamination partner for L-glutamine. Since B-cell mitochondria are well supplied with L-glutamate and L-glutamine, 2-ketoglutarate generation in the presence of these two neutral 2-keto acids may be an important prerequisite for their insulin secretory potency. High rates of transamination of 2-ketoglutarate were observed in the pancreatic B-cell mitochondria with the branched-chain amino acids L-leucine and L-valine, but not with L-norleucine. In connection with the ability of L-leucine to activate glutamate dehydrogenase, this high activity of the branched-chain amino acid aminotransferase in pancreatic B-cell mitochondria may provide an explanation for the insulin secretory potency of this amino acid.
    [Abstract] [Full Text] [Related] [New Search]