Reaction: Endohydrolysis of 1,3-α-L-galactosidic linkages in agarose, yielding agarotetraose as the major product
Glossary: agarose = a linear polysaccharide produced by some members of the Rhodophyta (red algae) made up from alternating D-galactose and 3,6-anhydro-α-L-galactopyranose residues joined by α-(1→3)- and β-(1→4)-linkages. In the field of oligosaccharides derived from agarose, carrageenans, etc., in which alternate residues are 3,6-anhydro sugars, the prefix ’neo’ designates an oligosaccharide whose non-reducing end is the anhydro sugar, and the absence of this prefix means that it is not.
neoagarobiose = 3,6-anhydro-α-L-galactopyranosyl-(1→3)-D-galactose
agarobiose = β-D-galactopyranosyl-(1→4)-3,6-anhydro-L-galactose
Other name(s): agarase (ambiguous); agaraseA33
Systematic name: agarose 3-glycanohydrolase
Comments: Requires Ca2+. The enzyme from Thalassomonas sp. can use agarose, agarohexaose and neoagarohexaose as substrate. The products of agarohexaose hydrolysis are dimers and tetramers, with agarotetraose being the predominant product, whereas hydrolysis of neoagarohexaose gives rise to two types of trimer. While the enzyme can also hydrolyse the highly sulfated agarose porphyran very efficiently, it cannot hydrolyse the related compounds κ-carrageenan (see EC 126.96.36.199) and ι-carrageenan (see EC 188.8.131.52) . See also EC 184.108.40.206, β-agarase.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
1. Potin, P., Richard, C., Rochas, C. and Kloareg, B. Purification and characterization of the α-agarase from Alteromonas agarlyticus (Cataldi) comb. nov., strain GJ1B. Eur. J. Biochem. 214 (1993) 599-607. [PMID: 8513809]
2. Ohta, Y., Hatada, Y., Miyazaki, M., Nogi, Y., Ito, S. and Horikoshi, K. Purification and characterization of a novel α-agarase from a Thalassomonas sp. Curr. Microbiol. 50 (2005) 212-216. [PMID: 15902469]