Premium
Inhibition of the lepidopteran amino acid co‐transporter KAAT1 by phenylglyoxal: role of arginine 76
Author(s) -
Castagna Michela,
Vincenti Sergio,
Marciani Paola,
Sacchi V. Franca
Publication year - 2002
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1046/j.1365-2583.2002.00327.x
Subject(s) - phenylglyoxal , arginine , biochemistry , transporter , amino acid , binding site , leucine , biology , xenopus , chemistry , gene
Phenylglyoxal (PGO), an arginine‐modifying reagent, is an irreversible inhibitor of KAAT1‐mediated leucine transport, expressed in Xenopus oocytes. The PGO effect was dose‐dependent and 5 m m PGO determined a V max reduction to 24% of the control, consistent with the covalent binding to transporter arginine residues not located in the leucine binding site. The use of labelled [ 14 C]PGO confirmed that the inhibitor binds KAAT1. The protein membrane domain contains seven arginine residues one of which, arginine 76, is conserved in the family of GABA transporters. Using site‐directed mutagenesis we showed that only arginine 76 is crucial for KAAT1 activity and is involved in PGO binding.