UniProt functional annotation for P07987



	UniProt functional annotation for P07987

UniProt code: P07987.

Organism: Hypocrea jecorina (Trichoderma reesei).

Taxonomy: Eukaryota; Fungi; Dikarya; Ascomycota; Pezizomycotina; Sordariomycetes; Hypocreomycetidae; Hypocreales; Hypocreaceae; Trichoderma.

Function: Exocellobiohydrolases (CBH) that catalyzes the hydrolysis of 1,4-beta-D-glucosidic bonds in cellulose to release the disaccharide cellobiose (Ref.3). The degradation of cellulose involves an interplay between different cellulolytic enzymes. Hydrolysis starts with endoglucanases (EGs), which cut internal beta-1,4-glucosidic bonds in cellulose to reduce the polymerization degree of the substrate and create new chain ends for exocellobiohydrolases (CBHs). The CBHs release the disaccharide cellobiose from the non-reducing end of the cellulose polymer chain. Finally, beta-1,4-glucosidases hydrolyze the cellobiose and other short cello-oligosaccharides into glucose units (Probable). {ECO:0000269|Ref.3, ECO:0000305}.

Catalytic activity: Reaction=Hydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose and cellotetraose, releasing cellobiose from the non-reducing ends of the chains.; EC=3.2.1.91; Evidence={ECO:0000269|Ref.3};

Biophysicochemical properties: Kinetic parameters: KM=17 uM for cellotriose {ECO:0000269|PubMed:12188666}; KM=2.6 uM for cellotetraose {ECO:0000269|PubMed:12188666}; KM=1.3 uM for cellopentaose {ECO:0000269|PubMed:12188666}; KM=14 uM for cellohexaose {ECO:0000269|PubMed:12188666}; Note=kcat is 0.06 sec(-1) with cellotriose as substrate, 4.1 sec(-1) with cellotetraose as substrate, 1.1 sec(-1) with cellopentaose as substrate and 14 sec(-1) with cellopentaose as substrate. {ECO:0000269|PubMed:12188666}; pH dependence: Optimum pH is 4-6. {ECO:0000269|PubMed:12188666};

Subcellular location: Secreted {ECO:0000269|Ref.3}.

Domain: The enzyme consists of two functional domains, a catalytic core joined to a carbohydrate-binding domain (CBM) by a serine-, threonine-, and proline-rich, highly glycosylated linker sequence. {ECO:0000305}.

Ptm: Asn-334 contains mainly a high-mannose-type glycan (Hex(7- 9)GlcNAc(2)) in a 3:1 ration with a single GlcNAc. Asn-313 was primarily unglycosylated with a small fraction (18%) bearing a single GlcNAc at this site. {ECO:0000250|UniProtKB:A0A024SH76}.

Miscellaneous: T.reesei produces two different exocellobiohydrolases. They are unique in that they can hydrolyze crystalline cellulose in the absence of endoglucanases.

Similarity: Belongs to the glycosyl hydrolase 6 (cellulase B) family. {ECO:0000305}.

Annotations taken from UniProtKB at the EBI.


Organism:		Hypocrea jecorina (Trichoderma reesei).
Taxonomy:		Eukaryota; Fungi; Dikarya; Ascomycota; Pezizomycotina; Sordariomycetes; Hypocreomycetidae; Hypocreales; Hypocreaceae; Trichoderma.



Function:		Exocellobiohydrolases (CBH) that catalyzes the hydrolysis of 1,4-beta-D-glucosidic bonds in cellulose to release the disaccharide cellobiose (Ref.3). The degradation of cellulose involves an interplay between different cellulolytic enzymes. Hydrolysis starts with endoglucanases (EGs), which cut internal beta-1,4-glucosidic bonds in cellulose to reduce the polymerization degree of the substrate and create new chain ends for exocellobiohydrolases (CBHs). The CBHs release the disaccharide cellobiose from the non-reducing end of the cellulose polymer chain. Finally, beta-1,4-glucosidases hydrolyze the cellobiose and other short cello-oligosaccharides into glucose units (Probable). {ECO:0000269\|Ref.3, ECO:0000305}.


Catalytic activity:		Reaction=Hydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose and cellotetraose, releasing cellobiose from the non-reducing ends of the chains.; EC=3.2.1.91; Evidence={ECO:0000269\|Ref.3};
Biophysicochemical properties:		Kinetic parameters: KM=17 uM for cellotriose {ECO:0000269\|PubMed:12188666}; KM=2.6 uM for cellotetraose {ECO:0000269\|PubMed:12188666}; KM=1.3 uM for cellopentaose {ECO:0000269\|PubMed:12188666}; KM=14 uM for cellohexaose {ECO:0000269\|PubMed:12188666}; Note=kcat is 0.06 sec(-1) with cellotriose as substrate, 4.1 sec(-1) with cellotetraose as substrate, 1.1 sec(-1) with cellopentaose as substrate and 14 sec(-1) with cellopentaose as substrate. {ECO:0000269\|PubMed:12188666}; pH dependence: Optimum pH is 4-6. {ECO:0000269\|PubMed:12188666};
Subcellular location:		Secreted {ECO:0000269\|Ref.3}.
Domain:		The enzyme consists of two functional domains, a catalytic core joined to a carbohydrate-binding domain (CBM) by a serine-, threonine-, and proline-rich, highly glycosylated linker sequence. {ECO:0000305}.
Ptm:		Asn-334 contains mainly a high-mannose-type glycan (Hex(7- 9)GlcNAc(2)) in a 3:1 ration with a single GlcNAc. Asn-313 was primarily unglycosylated with a small fraction (18%) bearing a single GlcNAc at this site. {ECO:0000250\|UniProtKB:A0A024SH76}.
Miscellaneous:		T.reesei produces two different exocellobiohydrolases. They are unique in that they can hydrolyze crystalline cellulose in the absence of endoglucanases.
Similarity:		Belongs to the glycosyl hydrolase 6 (cellulase B) family. {ECO:0000305}.