LMPD Database

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LMP010457

UniProt Annotations

Entry Information
Gene Nameheme oxygenase 1
Protein EntryHMOX1_ARATH
UniProt IDO48782
SpeciesArabidopsis
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative splicing; Named isoforms=2; Name=1; IsoId=O48782-1; Sequence=Displayed; Name=2; IsoId=O48782-2; Sequence=VSP_041652; Note=Derived from EST data. No experimental confirmation available.;
Biophysicochemical PropertiesKinetic parameters: KM=1.3 uM for hemin {ECO:0000269|PubMed:12481078, ECO:0000269|PubMed:19860740}; KM=1.9 uM for ferredoxin {ECO:0000269|PubMed:12481078, ECO:0000269|PubMed:19860740}; KM=420 uM for ascorbate {ECO:0000269|PubMed:12481078, ECO:0000269|PubMed:19860740}; pH dependence: Optimum pH is 7.2. {ECO:0000269|PubMed:12481078, ECO:0000269|PubMed:19860740};
Catalytic ActivityProtoheme + 3 AH(2) + 3 O(2) = biliverdin + Fe(2+) + CO + 3 A + 3 H(2)O. {ECO:0000269|PubMed:10072395, ECO:0000269|PubMed:12481078}.
Disruption PhenotypeLong hypocotyl, incomplete chloroplast and leaf development, lack of photoreversible phytochromes and lack of phytochromobilin, the phytochrome chromophore. No cotyledon expansion in response to bright-red light. Increased levels of jasmonate (JA) and constitutive expression of JA-inducible defense genes. Increased sensitivity to salt stress and no acclimation response to salinity. {ECO:0000269|PubMed:10072395, ECO:0000269|PubMed:10339624, ECO:0000269|PubMed:11135121, ECO:0000269|PubMed:12232145, ECO:0000269|PubMed:12324588, ECO:0000269|PubMed:12359912, ECO:0000269|PubMed:16428602, ECO:0000269|PubMed:17567636, ECO:0000269|PubMed:20979354, ECO:0000269|PubMed:21205037, ECO:0000269|PubMed:7690685}.
Enzyme RegulationActivated by ascorbate. {ECO:0000269|PubMed:12481078}.
FunctionKey enzyme in the synthesis of the chromophore of the phytochrome family of plant photoreceptors. Catalyzes the opening of the heme ring to form the open-chain tetrapyrrole biliverdin IX with the release of iron and carbon monoxide (CO). Produces specifically the biliverdin IX-alpha isomer. Can form complex with heme, is ferredoxin-dependent and its activity is increased in the presence of ascorbate. Plays a role in salt acclimation signaling. May affect the plastid-to-nucleus signaling pathway by perturbing tetrapyrrole synthesis. The plastid-to-nucleus signal plays an important role in the coordinated expression of both nuclear- and chloroplast-localized genes that encode photosynthesis-related proteins. {ECO:0000269|PubMed:10072395, ECO:0000269|PubMed:10339624, ECO:0000269|PubMed:11135121, ECO:0000269|PubMed:11172074, ECO:0000269|PubMed:12232145, ECO:0000269|PubMed:12324588, ECO:0000269|PubMed:12481078, ECO:0000269|PubMed:16428602, ECO:0000269|PubMed:19860740, ECO:0000269|PubMed:20979354, ECO:0000269|PubMed:21205037, ECO:0000269|PubMed:7690685}.
InductionBy salt treatment. Down-regulated by jasmonate. {ECO:0000269|PubMed:17567636, ECO:0000269|PubMed:20979354}.
Sequence CautionSequence=AAK52998.1; Type=Erroneous initiation; Note=Translation N-terminally extended.; Evidence={ECO:0000305};
SimilarityBelongs to the heme oxygenase family. {ECO:0000305}.
Subcellular LocationPlastid, chloroplast {ECO:0000269|PubMed:10072395, ECO:0000269|PubMed:19860740}.
Tissue SpecificityWidely expressed. {ECO:0000269|PubMed:10339624, ECO:0000269|PubMed:16428602, ECO:0000269|PubMed:20979354}.