Q6IWZ0 (OXLA_APLCA) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: L-amino-acid oxidase Short name=LAAO Short name=LAO EC=1.4.3.2 Alternative name(s): Escapin
Organism	Aplysia californica (California sea hare)
Taxonomic identifier	6500 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Lophotrochozoa › Mollusca › Gastropoda › Heterobranchia › Euthyneura › Euopisthobranchia › Aplysiomorpha › Aplysioidea › Aplysiidae › Aplysia

Protein attributes

Sequence length	535 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Catalyzes the oxidative deamination of positively charged L-amino acids L-Lys and L-Arg and, much less efficiently, of amino acids L-His and L-Tyr. Has antimicrobial activity. Inhibits growth of Gram-negative bacteria E.coli strain MC4100 (MIC=0.62 µg/ml), E.coli strain C921-b2, S.typhimurium strain AA 140 (MIC=0.62 µg/ml), P.aeruginosa strain PAO1 (MIC=0.31 µg/ml) and V.harveyi strain BB170 (MIC=0.25 µg/ml). Inhibits growth of Gram-positive bacteria S.aureus stain 6835 (MIC=0.31 µg/ml), S.pyogenes strain NZ131 (MIC=0.62 µg/ml), B.subtilis strain 168 (MIC=2.50 µg/ml) and B.subtilis strain WB600 (MIC=2.50 µg/ml). The antibacterial effect can be bacteriostatic, mediated mostly by H2O2, as well as bactericidal. The latter appears to be due to unstable intermediates generated from alpha-keto-epsilon-aminocaproic acid, an intermediate of escapin-deaminated L-Lys, and H2O2. The bactericidal effect is stronger at lower pH levels. Intermediates generated from L-Arg have no bactericidal effect. Inhibits growth of yeast species S.cerevisiae strain BY4761 (MIC=5.0 µg/ml) and C.krusei (MIC=5.0 µg/ml). Inhibits growth of C.sphaerospermum in a lysine-dependent manner. As components of ink, products from escapin's enzymatic activity may play a role in deterring eukaryotic predators. Ref.1 Ref.2 Ref.3 Ref.5
Catalytic activity	An L-amino acid + H2O + O2 = a 2-oxo acid + NH3 + H2O2. Ref.1 Ref.2 Ref.3 Ref.4 Ref.5
Cofactor	FAD. Ref.1 Ref.5
Subcellular location	Secreted Ref.2.
Tissue specificity	Expressed exclusively in the ink gland. Within the ink gland, it is only detected in amber vesicles (at protein level). Ref.2
Post-translational modification	Not glycosylated. Ref.1 Ref.5
Sequence similarities	Belongs to the flavin monoamine oxidase family.
Biophysicochemical properties	Kinetic parameters: KM=85.5 µM for L-Lys Ref.1 Ref.5 KM=120.5 µM for L-Arg Ref.5 Vmax=4.5 µmol/sec/µg enzyme with L-Lys as substrate Ref.5 Vmax=5.5 µmol/sec/µg enzyme with L-Arg as substrate Ref.5

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Ligand	FAD Flavoprotein
Molecular function	Antibiotic Antimicrobial Fungicide Oxidoreductase
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological_process	defense response to bacterium Inferred from direct assay Ref.1Ref.3. Source: UniProtKB defense response to fungus Inferred from electronic annotation. Source: UniProtKB-KW killing of cells of other organism Inferred from electronic annotation. Source: UniProtKB-KW
Cellular_component	extracellular region Inferred from direct assay Ref.2. Source: UniProtKB
Molecular_function	L-amino-acid oxidase activity Inferred from direct assay Ref.1Ref.3Ref.4. Source: UniProtKB
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Signal peptide	1 – 18	18	Ref.5
	Chain	19 – 535	517	L-amino-acid oxidase Ref.5		PRO_5000093471
Regions
	Nucleotide binding	46 – 47	2	FAD By similarity UniProtKB P81382
	Nucleotide binding	66 – 67	2	FAD By similarity UniProtKB P81382
	Nucleotide binding	91 – 94	4	FAD By similarity UniProtKB P81382
	Nucleotide binding	513 – 518	6	FAD By similarity UniProtKB P81382
	Nucleotide binding	513 – 514	2	Substrate By similarity UniProtKB P81382
Sites
	Binding site	74	1	FAD By similarity UniProtKB P81382
	Binding site	94	1	Substrate By similarity UniProtKB P81382
	Binding site	406	1	Substrate By similarity UniProtKB P81382

Sequences

	Sequence		Length	Mass (Da)
	Q6IWZ0 [UniParc]. Last modified July 5, 2004. Version 1. Checksum: 4F288F95F9B423FC	FASTA	535	60,300
	10 20 30 40 50 60 MSSAFLLLAC ALVISVHADG VCRNRRQCNK EVCGSSYDVA IVGAGPGGAN SAYMLRESGL 70 80 90 100 110 120 DIAVFEYSDR VGGRLFTYQL PNTPDVNLEI GGMRFIEGAM HRLWKVISEL GLTPKVFKEG 130 140 150 160 170 180 FGKEGRQRFY LRGQSLTKKQ VKSGDVPYDL SPEEKANQGR LVEYYLEKLT GLQLNGGPLK 190 200 210 220 230 240 REVALKLTVP DGRFLYDLTF DEALDLVASP EGKEFARDTH VFTSEVTLDA SAISIFDDHL 250 260 270 280 290 300 GEDYYGSEIY TLEEGMSSVP QGLLQTFLDA AKSNEFFPNN HLKALRRRTN GQYVLYFEPT 310 320 330 340 350 360 TSKDGQTTIN YLEPLKVVCA QRVILAMPVY ALRQLDWSQL RNDRATQAYR AVRPMPASKV 370 380 390 400 410 420 FMTFDQPWWL QNERKSWVTK SDALFSQMYD WQKSEASGDY ILIASYADGL KAQYLRELKN 430 440 450 460 470 480 QGEDIPGSDP GYNQVTVPLK DAILEHLTEA YGVERDSIPE PVTAASQFWT DYPFGCGWIT 490 500 510 520 530 WRAGYHFDDV ISTMRRPSLK DEVYVVGSDY SWGLISSWIE GALETSENVI NDYFL

References

[1]	"Cloning, characterization and expression of escapin, a broadly antimicrobial FAD-containing L-amino acid oxidase from ink of the sea hare Aplysia californica." Yang H., Johnson P.M., Ko K.C., Kamio M., Germann M.W., Derby C.D., Tai P.C. J. Exp. Biol. 208:3609-3622(2005) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], PARTIAL PROTEIN SEQUENCE, FUNCTION, CATALYTIC ACTIVITY, COFACTOR, BIOPHYSICOCHEMICAL PROPERTIES, ABSENCE OF GLYCOSYLATION. Tissue: Ink and Ink gland.
[2]	"Packaging of chemicals in the defensive secretory glands of the sea hare Aplysia californica." Johnson P.M., Kicklighter C.E., Schmidt M., Kamio M., Yang H., Elkin D., Michel W.C., Tai P.C., Derby C.D. J. Exp. Biol. 209:78-88(2006) [PubMed] [Europe PMC] [Abstract] Cited for: SUBCELLULAR LOCATION, TISSUE SPECIFICITY.
[3]	"Identification of potent bactericidal compounds produced by escapin, an L-amino acid oxidase in the ink of the sea hare Aplysia californica." Ko K.C., Wang B., Tai P.C., Derby C.D. Antimicrob. Agents Chemother. 52:4455-4462(2008) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, CATALYTIC ACTIVITY. Tissue: Ink.
[4]	"The chemistry of escapin: identification and quantification of the components in the complex mixture generated by an L-amino acid oxidase in the defensive secretion of the sea snail Aplysia californica." Kamio M., Ko K.C., Zheng S., Wang B., Collins S.L., Gadda G., Tai P.C., Derby C.D. Chemistry 15:1597-1603(2009) [PubMed] [Europe PMC] [Abstract] Cited for: CATALYTIC ACTIVITY. Tissue: Ink.
[5]	"Effects of sea hare ink secretion and its escapin-generated components on a variety of predatory fishes." Nusnbaum M., Derby C.D. Biol. Bull. 218:282-292(2010) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.

Cross-references

Sequence databases
EMBL GenBank DDBJ	AY615888 mRNA. Translation: AAT12273.1.
RefSeq	NP_001191570.1. NM_001204641.1.
UniGene	Acl.23634.
3D structure databases
ProteinModelPortal	Q6IWZ0.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
GeneID	100533346.
Enzyme and pathway databases
BRENDA	1.4.3.2. 629.
Family and domain databases
InterPro	IPR002937. Amino_oxidase. [Graphical view]
Pfam	PF01593. Amino_oxidase. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

OXLA_APLCA

Accession

Primary (citable) accession number: Q6IWZ0

Entry history

Integrated into UniProtKB/Swiss-Prot:	October 19, 2011
Last sequence update:	July 5, 2004
Last modified:	October 3, 2012
This is version 30 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)