Localization and measurement of extracellular plant galactosidases

A simple, rapid and sensitive procedure for the identification and determination of plant extracellular α-galactosidase and β-galactosidase is described using callus cultures and seedlings from tomato. Synthetic substrates (1-naphthyl- and p-nitrophenyl-α-D- and β-D-galactopyranosides) were used for the identification and determination of intracellular and extracellular activity of α-galactosidase and β-galactosidase, respectively. Many iminosugars or azasugars are strong glycosidase inhibitors and some of them show promising chemotherapeutic effects against viral diseases, and are potentially antidiabetic agents, as well as antitumor agents. These facts initiated our interest in a rapid and sensitive assay to determine activity of α-galactosidase and β-galactosidase in plant tissues. The results presented here show the potential of the assay of the activity of intracellular and extracellular galactosidases of plant origin in inhibitory and/or biotechnological studies.