Beta-porphyranase
| Beta-porphyranase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 3.2.1.178 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| |||||||||
Beta porphyranase is an enzyme responsible for the degradation of porphyran, which composes the cell wall of red algae. So far only five β-porphyranases have been identified: PorA and PorB are found in the marine bacteria Zobellia galactinovirans. A wild-type porphyranase activity has been found in Pseudoalteromonas atlantica. BpGH16B and BpGH86A have been found in the human gut bacterium, Bacteroides plebeius, of Japanese individuals.
Porphyran, the major water soluble polysaccharide of Porphyra has a linear structure composed of 4-linked α-l-galactopyranose-6-sulfate (L6S) residues and 3-linked β-d-galactopyranose (G) residues. Beta porphyranase (EC 3.2.1 178; 3= Hydrolase; 3.2= Glycosylase; 3.2.1 = Glycosidases (enzymes hydrolyzing O- and S- glycosyl compounds)) acts as a glycosidase to catalyze the following chemical reaction:
- Hydrolysis of beta-D-galactopyranose-(1->4)-alpha-L-galactopyranose-6-sulfate linkages in porphyran
The backbone of porphyran consists largely (~70%) of (1->3)-linked beta-D-galactopyranose followed by (1->4)-linked alpha-L-galactopyranose-6-sulfate.