Open AccessTransport of arginine and ornithine into isolated mitochondria of Saccharomyces cerevisiae
Author(s) -
Soetens Oriane,
Crabeel Marjolaine,
El Moualij Benaïssa,
Duyckaerts Claire,
Sluse Francis
Publication year - 1998
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1998.2580702.x
Subject(s) - arginine , ornithine , biochemistry , histidine , saccharomyces cerevisiae , amino acid , antiporter , lysine , mutant , ornithine decarboxylase antizyme , biology , chemistry , ornithine decarboxylase , enzyme , membrane , yeast , gene
In this work we have characterised the transport of L ‐arginine and L ‐ornithine into mitochondria isolated from a wild‐type Saccharomyces cerevisiae strain and an isogenic arg11 knock‐out mutant. The Arg11 protein (Arg11p) is a mitochondrial carrier required for arginine biosynthesis [Crabeel, M., Soetens, O., De Rijcke, M., Pratiwi, R. & Pankiewicz, R. (1996) J. Biol. Chem. 271 , 25 011−25 019]. Reconstitution experiments have confirmed that it is an L ‐ornithine carrier also transporting L ‐arginine and L ‐lysine by order of decreasing affinity, but not L ‐histidine [Palmieri, L., De Marco, V., Iacobazzi, V., Palmieri, F., Runswick, M. & Walker, J. (1997) FEBS Lett. 410 , 447−451]. Evidence is presented here that the mitochondrial inner membrane contains an L ‐arginine and L ‐ornithine transporting system distinct from Arg11p, in keeping with the arginine leaky phenotype of arg11 knock‐out mutants. The newly characterised carrier, which we propose to name Bac1p (basic amino acid carrier), behaves as an antiporter catalysing the electroneutral exchange of the basic amino acids L ‐arginine, L ‐lysine, L ‐ornithine and L ‐histidine and displays the highest affinity for L ‐arginine ( K m of 30 μM). L ‐Arginine uptake has a pH optimum in the range of 7.5−9 and is inhibited by several sulphydryl reagents, by pyridoxal 5′‐phosphate and by cations.