UniProt functional annotation for P42293

UniProt code: P42293.

Organism: Bacillus subtilis (strain 168).
Taxonomy: Bacteria; Firmicutes; Bacilli; Bacillales; Bacillaceae; Bacillus.
 
Function: Involved in the degradation of arabinan and is a key enzyme in the complete degradation of the plant cell wall. Catalyzes the internal cleavage of alpha-(1->5)-L-arabinofuranosyl residues of the alpha-1,5-L-arabinan to produce arabino-oligosaccharides and L- arabinose. It is also active toward linear branched sugar beet arabinan, and pectin from apple. {ECO:0000269|PubMed:18408032, ECO:0000269|PubMed:20883454}.
 
Catalytic activity: Reaction=Endohydrolysis of (1->5)-alpha-arabinofuranosidic linkages in (1->5)-arabinans.; EC=3.2.1.99; Evidence={ECO:0000269|PubMed:20883454};
Cofactor: Name=Ca(2+); Xref=ChEBI:CHEBI:29108; Evidence={ECO:0000305}; Note=Binds 1 Ca(2+) ion per subunit. {ECO:0000305};
Biophysicochemical properties: Kinetic parameters: KM=0.11 mM for linear-alpha-1,5-L-arabinan {ECO:0000269|PubMed:18408032, ECO:0000269|PubMed:20883454}; KM=2 mM for linear-alpha-1,5-L-arabinan (at pH 7.0 and 50 degrees Celsius) {ECO:0000269|PubMed:18408032, ECO:0000269|PubMed:20883454}; Vmax=0.25 mmol/min/mg enzyme for linear-alpha-1,5-L-arabinan (at pH 7.0 and 50 degrees Celsius) {ECO:0000269|PubMed:18408032, ECO:0000269|PubMed:20883454}; pH dependence: Optimum pH is 7. {ECO:0000269|PubMed:18408032, ECO:0000269|PubMed:20883454}; Temperature dependence: Optimum temperature is 50 degrees Celsius. It remains fully active after 30 minutes of preincubation at 50 degrees Celsius, however, after preincubation at 60 degrees Celsius, the residual activity is only 15%. {ECO:0000269|PubMed:18408032, ECO:0000269|PubMed:20883454};
Pathway: Glycan metabolism; L-arabinan degradation.
Subunit: Homodimer. {ECO:0000269|PubMed:20883454}.
Subcellular location: Secreted {ECO:0000269|PubMed:18408032, ECO:0000269|PubMed:18607095, ECO:0000269|PubMed:20883454}.
Induction: Repressed by glucose, and induced by pectin and arabinan. {ECO:0000269|PubMed:18408032}.
Disruption phenotype: No visible phenotype. Double mutant abn2/abnA induce an almost complete loss of this activity. {ECO:0000269|PubMed:18408032}.
Similarity: Belongs to the glycosyl hydrolase 43 family. {ECO:0000305}.

Annotations taken from UniProtKB at the EBI.