p-Aminobenzyl 1-thio-?-D-galactopyranoside?Agarose has been used in the column for the purification of Bacillus circulans sp. alkalophilus b-galactosidase (Bca-b-gal). It has also been used in the derivatization of affinity matrix of agarose to perform affinity chromatography for the purification ofP. haloplanktis ?-galactosidase.