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UniProt functional annotation for Q29495 | ||
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| UniProt code: Q29495. |
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| Organism: | |
Ovis aries (Sheep). |
| Taxonomy: | |
Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Laurasiatheria; Artiodactyla; Ruminantia; Pecora; Bovidae; Caprinae; Ovis. |
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| Function: | |
Controls the night/day rhythm of melatonin production in the pineal gland. Catalyzes the N-acetylation of serotonin into N- acetylserotonin, the penultimate step in the synthesis of melatonin. {ECO:0000269|PubMed:15644438}. |
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| Catalytic activity: | |
Reaction=2-arylethylamine + acetyl-CoA = CoA + H(+) + N-acetyl-2- arylethylamine; Xref=Rhea:RHEA:20497, ChEBI:CHEBI:15378, ChEBI:CHEBI:55469, ChEBI:CHEBI:57287, ChEBI:CHEBI:57288, ChEBI:CHEBI:77827; EC=2.3.1.87; Evidence={ECO:0000269|PubMed:10319816, ECO:0000269|PubMed:11884405, ECO:0000269|PubMed:11902838, ECO:0000269|PubMed:18362150}; |
| Biophysicochemical properties: | |
Kinetic parameters: KM=0.29 mM for acetyl-CoA {ECO:0000269|PubMed:11313340, ECO:0000269|PubMed:11884405}; KM=0.17 mM for tryptamine {ECO:0000269|PubMed:11313340, ECO:0000269|PubMed:11884405}; KM=0.20 mM for tryptamine {ECO:0000269|PubMed:11313340, ECO:0000269|PubMed:11884405}; KM=0.31 mM for 5-hydroxytryptamine {ECO:0000269|PubMed:11313340, ECO:0000269|PubMed:11884405}; KM=3.4 mM for phenylethylamine {ECO:0000269|PubMed:11313340, ECO:0000269|PubMed:11884405}; KM=3.4 mM for tyramine {ECO:0000269|PubMed:11313340, ECO:0000269|PubMed:11884405}; |
| Pathway: | |
Aromatic compound metabolism; melatonin biosynthesis; melatonin from serotonin: step 1/2. {ECO:0000305}. |
| Subunit: | |
Monomer. Interacts with several 14-3-3 proteins, including YWHAB, YWHAE, YWHAG and YWHAZ, preferentially when phosphorylated at Thr-31. Phosphorylation on Ser-205 also allows binding to YWHAZ, but with a 10-fold lower affinity. The interaction with YWHAZ considerably increases affinity for arylalkylamines and acetyl-CoA and protects the enzyme from dephosphorylation and proteasomal degradation. It may also prevent thiol-dependent inactivation. The physiological stoichiometry of the interaction is not clear. In vitro studies show either 1:2 (i.e. 1 AANAT molecule per YWHAZ dimer) (PubMed:11427721) or 2:2 (PubMed:11336675). {ECO:0000269|PubMed:10319816, ECO:0000269|PubMed:11336675, ECO:0000269|PubMed:11427721, ECO:0000269|PubMed:11884405, ECO:0000269|PubMed:14578935, ECO:0000269|PubMed:15644438}. |
| Subcellular location: | |
Cytoplasm {ECO:0000250|UniProtKB:Q16613}. |
| Tissue specificity: | |
Highest expression in the pineal gland, followed by retina. Expressed at much lower levels in brainstem and pituitary gland. AANAT activity also detected at low levels in the olfactory lobe. {ECO:0000269|PubMed:7502081}. |
| Induction: | |
Exhibits night/day variations with a 7-fold increased activity at night. At the mRNA level, the nocturnal increase is lower than 2-fold. {ECO:0000269|PubMed:11313340, ECO:0000269|PubMed:15644438, ECO:0000269|PubMed:7502081}. |
| Ptm: | |
cAMP-dependent phosphorylation on both N-terminal Thr-31 and C- terminal Ser-205 regulates AANAT activity by promoting interaction with 14-3-3 proteins. {ECO:0000250}. |
| Similarity: | |
Belongs to the acetyltransferase family. AANAT subfamily. {ECO:0000305}. |
Annotations taken from UniProtKB at the EBI.