Interference ofL-Arginine Analogues withL-Arginine Transport Mediated by the y+Carrier hCAT-2B

摘要: The inducible human cationic amino acid transporter hCAT-2B was expressed inXenopus laevisoocytes, and this system used to test the effect of several NO synthase (NOS) inhibitors and/orL-arginine analogues onL-arginine transport by y+carrier.L-NG-Methyl-L-arginine (L-NMA), asymmetricalL-NG,NG-dimethyl-L-arginine (L-ADMA),L-N5-(1-iminoethyl)-ornithine (L-NIO),L-NG-nitro-L-arginine (L-NNA), andL-NG-nitro-L-arginine methyl ester (L-NAME) all inhibited NOS II extracted from RAW 264.7 macrophages induced with bacterial lipopolysaccharide. L-NMA, L-ADMA, L-NIO also competed withL-arginine for hCAT-2B, whereas L-NNA L-NAME did not. twoL-arginine analogues, symmetricalNG,N′-dimethyl-L-arginine (L-SDMA) α-amino-δ-isothioureidovaleric (AITV), as well asL-lysine, not block enzymatic activity II, but compete forL-arginine mediated hCAT-2B.L-Lysine L-SDMA were transported efficiently exchanged against intracellularL-arginine, resulting in anL-arginine depletion cells. AITV a much poorer substrate had only little on intracellularL-arginine concentrations. These data indicate that recognition differs markedly between inducibleL-arginine differentL-arginine having affinity one or both these proteins.