ID   APX1_HYDVD              Reviewed;         367 AA.
AC   Q539E5;
DT   05-JUL-2005, integrated into UniProtKB/Swiss-Prot.
DT   24-MAY-2005, sequence version 1.
DT   25-MAY-2022, entry version 53.
DE   RecName: Full=Putative ascorbate peroxidase;
DE            EC=1.11.1.11;
DE   AltName: Full=HvAPX1;
DE   Flags: Precursor;
GN   Name=APX1;
OS   Hydra viridissima (Green hydra) (Chlorohydra viridissima).
OC   Eukaryota; Metazoa; Cnidaria; Hydrozoa; Hydroidolina; Anthoathecata;
OC   Aplanulata; Hydridae; Hydra.
OX   NCBI_TaxID=6082;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], AND DEVELOPMENTAL STAGE.
RC   STRAIN=A99;
RX   PubMed=15914659; DOI=10.1242/jeb.01571;
RA   Habetha M., Bosch T.C.G.;
RT   "Symbiotic Hydra express a plant-like peroxidase gene during oogenesis.";
RL   J. Exp. Biol. 208:2157-2165(2005).
CC   -!- FUNCTION: May play a role in the protection of oocyte incorporated
CC       cells from rapid apoptotic degradation.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=H2O2 + L-ascorbate = 2 H2O + L-dehydroascorbate;
CC         Xref=Rhea:RHEA:22996, ChEBI:CHEBI:15377, ChEBI:CHEBI:16240,
CC         ChEBI:CHEBI:38290, ChEBI:CHEBI:58539; EC=1.11.1.11;
CC   -!- COFACTOR:
CC       Name=heme b; Xref=ChEBI:CHEBI:60344;
CC         Evidence={ECO:0000255|PROSITE-ProRule:PRU00297};
CC       Note=Binds 1 heme b (iron(II)-protoporphyrin IX) group per subunit.
CC       {ECO:0000255|PROSITE-ProRule:PRU00297};
CC   -!- DEVELOPMENTAL STAGE: Expressed exclusively during oogenesis.
CC       {ECO:0000269|PubMed:15914659}.
CC   -!- MISCELLANEOUS: The gene for this protein may have been transferred
CC       horizontally following an endosymbiotic event early in evolution of the
CC       Hydra lineage as an RNA or cDNA intermediate.
CC   -!- SIMILARITY: Belongs to the peroxidase family. {ECO:0000305}.
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DR   EMBL; AY608909; AAU07981.1; -; mRNA.
DR   AlphaFoldDB; Q539E5; -.
DR   SMR; Q539E5; -.
DR   PeroxiBase; 2285; HviNAnPrx01.
DR   GO; GO:0020037; F:heme binding; IEA:InterPro.
DR   GO; GO:0016688; F:L-ascorbate peroxidase activity; IEA:UniProtKB-EC.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0034599; P:cellular response to oxidative stress; IEA:InterPro.
DR   GO; GO:0042744; P:hydrogen peroxide catabolic process; IEA:UniProtKB-KW.
DR   InterPro; IPR044831; Ccp1-like.
DR   InterPro; IPR002016; Haem_peroxidase.
DR   InterPro; IPR010255; Haem_peroxidase_sf.
DR   InterPro; IPR019793; Peroxidases_heam-ligand_BS.
DR   PANTHER; PTHR31356; PTHR31356; 1.
DR   Pfam; PF00141; peroxidase; 1.
DR   PRINTS; PR00458; PEROXIDASE.
DR   SUPFAM; SSF48113; SSF48113; 1.
DR   PROSITE; PS00435; PEROXIDASE_1; 1.
DR   PROSITE; PS50873; PEROXIDASE_4; 1.
PE   2: Evidence at transcript level;
KW   Disulfide bond; Glycoprotein; Heme; Hydrogen peroxide; Iron; Metal-binding;
KW   Oxidoreductase; Peroxidase; Signal.
FT   SIGNAL          1..16
FT                   /evidence="ECO:0000255"
FT   CHAIN           17..367
FT                   /note="Putative ascorbate peroxidase"
FT                   /id="PRO_0000023637"
FT   ACT_SITE        58
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00297"
FT   SITE            54
FT                   /note="Transition state stabilizer"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00297"
FT   CARBOHYD        119
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        239
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        356
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   DISULFID        60..66
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00297"
SQ   SEQUENCE   367 AA;  40790 MW;  91E0A494F416A10D CRC64;
     MVPVIWLTVL IVLVDSLQII PTFHDFQRAK TDLLGLIESV KRGDDLPMIA GTVRLAFHDC
     IGKGKCDGCI DHSKPGNAGL KRVTDRLDAL YDASYKGKIS RADFYALASV TALTRSTANL
     SDKYNGLRKF KVGRKDCSTS PVESIDSSDI PRGSDGTSKT LQFFKSEFGM KTQEAVALLG
     AHTLGRCSLQ NSGFVGSWVD QRFSTAPPGE ENLSPTSILD NAYYRMIIDI VPWTQVNING
     TRIQWQEPSN SIPNDKLPES KRSPLLLNSD MAISWIIKPS DALGTVSCRP TSLKTPCRHS
     NAHTFAKIYA KNNALWVKDF TKAFNKMIEM NENKLRKAPI FNGYFDEMNS HDEPINESVD
     EISEDIF