Alpha-agarase. Does not hydrolyze agarotetraose, agarohexaose, kappa-carrageenan, iota-carrageenan or lambda-carrageenan. Endohydrolysis of 1,3-alpha-L-galactosidic linkages in agarose, yielding agarotetraose as the major product. Optimum pH is 7.2. Active between pH 6.0 and 9.0. Inactive above 60 degrees Celsius. Homodimer. Belongs to the glycosyl hydrolase 96 family.