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Characteristics of an Uptake System for α‐Aminoisobutyric Acid in Leishmania tropica Promastigotes 1
Author(s) -
LEPLEY PEGGY R.,
MUKKADA ANTONY J.
Publication year - 1983
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1983.tb01030.x
Subject(s) - aminoisobutyric acid , glycine , methionine , chemistry , cysteine , serine , amino acid , biochemistry , alanine , intracellular , kinetics , reagent , biophysics , biology , enzyme , organic chemistry , physics , quantum mechanics
.Leishmania tropica promastigotes transport α‐aminoisobutyric acid (AIB), the nonmetabolizable analog of neutral amino acids, against a substantial concentration gradient. AIB is not incorporated into cellular material but accumulates within the cells in an unaltered form. Intracellular AIB exchanges with external AIB. Various energy inhibitors (amytal, HOQNO, KCN, DNP, CCCP, and arsenate) and sulfhydryl reagents (NEM, pCMB, and iodoacetate) severely inhibit uptake. The uptake system is saturable with reference to AIB‐and the Lineweaver‐Burk plots show biphasic kinetics suggesting the involvement of two transport systems. AIB shares a common transport system with alanine, cysteine, glycine, methionine, serine, and proline. Uptake is regulated by feedback inhibition and transinhibition.