The interaction between poly(acrylamide) gels carrying phenylboronic acid (PB gel) and catechol moieties (CAT gel) respectively is investigated. The PB gel forms an assembly with the CAT gel on a macroscopic scale in basic aqueous media. The adhesion strength is estimated by stress-strain measurements. The assembly and disassembly of the gels are reversibly switched by varying the pH of the medium. The adhesion strength is tunable by competitive monosaccharide molecules in accordance with the association constant with PB moieties.