title: Unexpected additional mode of energization of amino-acid transport into Ehrlich cells.
abstract: Ehrlich cells treated with dinitrophenol and iodoacetate rapidly recover their 30-sec uptake of 2-(methyl-amino)-isobutyrate on treatment with 0.1 mM phenazine methosulfate + 20 mM sodium ascorbate before they begin to recover from the severely depressed ATP levels and alkali-ion gradients. Addition of 10 mM pyruvate also restores uptake of methylaminoisobutyrate before the alkali-ion gradients rise. This restoration is prevented by rotenone, but rotenone does not handicap restoration by phenazine methosulfate/ascorbate. Na+-independent uptake of 2-aminonorbornane-2-carboxylate by Ehrlich cells is affected the same way. Quinacrine almost completely suppresses uptake of methylaminoisobutyrate within the 30-sec uptake test, even when ATP levels are sustained by pyruvate and alkali-ion gradients are not depressed. Ouabain prevents restoration of both Na+-dependent and Na+-independent amino-acid transport by phenazine methosulfate/ascorbate or pyruvate. We interpret these results to indicate that amino-acid transport can be energized not only by known means, but also by reducing equivalents, which presumably reach the plasma membrane in the form of NADH from the mitochondria when the source of energy is pyruvate. In support of this hypothesis, the distribution of methylaminoisobutyrate between plasma membrane vesicles and their supporting media was influenced in the predictable way by NADH, quinacrine, and an uncoupling agent, proceeding on the assumption that more of the vesicles had the everted rather than the natural orientation.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001386:Azides / Q000494:pharmacology; D001693:Biological Transport, Active; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003486:Cyanides / Q000494:pharmacology; D007700:Kinetics; D008773:Methylphenazonium Methosulfate / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D011796:Quinacrine / Q000494:pharmacology; D012402:Rotenone / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism
chemical_list: D000596:Amino Acids; D001386:Azides; D003486:Cyanides; D012402:Rotenone; D008773:Methylphenazonium Methosulfate; D010042:Ouabain; D000255:Adenosine Triphosphate; D012964:Sodium; D011796:Quinacrine; D011188:Potassium
references.citation: Biochem Biophys Res Commun. 1976 Oct 18;72(4):1548-53
references.pmid: 187187
references.citation: FEBS Lett. 1976 Oct 1;68(2):153-6
references.pmid: 185085
references.citation: J Biol Chem. 1971 Oct 10;246(19):5857-61
references.pmid: 4331061
references.citation: Biochim Biophys Acta. 1973 Dec 28;300(4):487-522
references.pmid: 4130564
references.citation: Biochim Biophys Acta. 1966 May 12;120(1):165-9
references.pmid: 4289762
references.citation: J Biol Chem. 1974 May 10;249(9):2793-800
references.pmid: 4275174
references.citation: Biochemistry. 1970 Sep 15;9(19):3669-77
references.pmid: 4252211
references.citation: Biochim Biophys Acta. 1976 Jun 17;436(2):424-37
references.pmid: 6067
references.citation: Biochim Biophys Acta. 1974 Mar 29;339(3):419-25
references.pmid: 4857890
references.citation: Biochim Biophys Acta. 1974 Aug 9;356(3):319-30
references.pmid: 4858486
references.citation: Biochem J. 1973 May;134(1):11-26
references.pmid: 4723218
references.citation: Biochim Biophys Acta. 1972 May 9;266(2):494-504
references.pmid: 5038272
references.citation: Biochim Biophys Acta. 1971 Oct 12;249(1):15-33
references.pmid: 5141124
references.citation: J Gen Physiol. 1966 Sep;50(1):203-24
references.pmid: 5971029