L-amino-acid oxidase (LAAO) (LAO) (EC 1.4.3.2) (EC 1.4.3.25) (Interleukin-4-induced protein 1) (IL4-induced protein 1) (hIL4I1) (Protein Fig-1) (hFIG1)
1_MAPLA 6_ LHLLV 11_ LVPIL 16_ LSLVA 21_ SQDWK 26_ AERSQ 31_ DPFEK 36_ CMQDP 41_ DYEQL 46_ LKVVT 51_ WGLNR 56_ TLKPQ 61_ RVIVV 66_ GAGVA 71_ GLVAA 76_ KVLSD 81_ AGHKV 86_ TILEA 91_ DNRIG 96_ GRIFT 101_ YRDQN 106_ TGWIG 111_ ELGAM 116_ RMPSS 121_ HRILH 126_ KLCQG 131_ LGLNL 136_ TKFTQ 141_ YDKNT 146_ WTEVH 151_ EVKLR 156_ NYVVE 161_ KVPEK 166_ LGYAL 171_ RPQEK 176_ GHSPE 181_ DIYQM 186_ ALNQA 191_ LKDLK 196_ ALGCR 201_ KAMKK 206_ FERHT 211_ LLEYL 216_ LGEGN 221_ LSRPA 226_ VQLLG 231_ DVMSE 236_ DGFFY 241_ LSFAE 246_ ALRAH 251_ SCLSD 256_ RLQYS 261_ RIVGG 266_ WDLLP 271_ RALLS 276_ SLSGL 281_ VLLNA 286_ PVVAM 291_ TQGPH 296_ DVHVQ 301_ IETSP 306_ PARNL 311_ KVLKA 316_ DVVLL 321_ TASGP 326_ AVKRI 331_ TFSPP 336_ LPRHM 341_ QEALR 346_ RLHYV 351_ PATKV 356_ FLSFR 361_ RPFWR 366_ EEHIE 371_ GGHSN 376_ TDRPS 381_ RMIFY 386_ PPPRE 391_ GALLL 396_ ASYTW 401_ SDAAA 406_ AFAGL 411_ SREEA 416_ LRLAL 421_ DDVAA 426_ LHGPV 431_ VRQLW 436_ DGTGV 441_ VKRWA 446_ EDQHS 451_ QGGFV 456_ VQPPA 461_ LWQTE 466_ KDDWT 471_ VPYGR 476_ IYFAG 481_ EHTAY 486_ PHGWV 491_ ETAVK 496_ SALRA 501_ AIKIN 506_ SRKGP 511_ ASDTA 516_ SPEGH 521_ ASDME 526_ GQGHV 531_ HGVAS 536_ SPSHD 541_ LAKEE 546_ GSHPP 551_ VQGQL 556_ SLQNT 561_THTRT
1: Secreted L-amino-acid oxidase that acts as a key immunoregulator (PubMed:17356132, PubMed:32818467, PubMed:32866000). Has preference for L-aromatic amino acids: converts phenylalanine (Phe), tyrosine (Tyr) and tryptophan (Trp) to phenylpyruvic acid (PP), hydroxyphenylpyruvic acid (HPP), and indole-3-pyruvic acid (I3P), respectively (PubMed:17356132, PubMed:32818467, PubMed:32866000). Also has weak L-arginine oxidase activity (PubMed:26673964). Acts as a negative regulator of anti-tumor immunity by mediating Trp degradation via an indole pyruvate pathway that activates the transcription factor AHR (PubMed:32818467, PubMed:32866000). IL4I1-mediated Trp catabolism generates I3P, giving rise to indole metabolites (indole-3-acetic acid (IAA) and indole-3-aldehyde (I3A)) and kynurenic acid, which act as ligands for AHR, a ligand-activated transcription factor that plays important roles in immunity and cancer (PubMed:32818467, PubMed:32866000). AHR activation by indoles following IL4I1-mediated Trp degradation enhances tumor progression by promoting cancer cell motility and suppressing adaptive immunity (PubMed:32818467). Also has an immunoregulatory function in some immune cells, probably by mediating Trp degradation and promoting downstream AHR activation: inhibits T-cell activation and proliferation, promotes the differentiation of naive CD4(+) T-cells into FOXP3(+) regulatory T-cells (Treg) and regulates the development and function of B-cells (PubMed:17356132, PubMed:25446972, PubMed:25778793, PubMed:28891065). Also regulates M2 macrophage polarization by inhibiting T-cell activation (By similarity). Also has antibacterial properties by inhibiting growth of Gram negative and Gram positive bacteria through the production of NH4(+) and H2O2 (PubMed:23355881)