Glucosinolate breakdown in crushed leaves of tgg1 or tgg2 single mutants was comparable to that of wild-type; indicating redundant enzyme function. In contrast; leaf extracts of tgg1 tgg2 double mutants had undetectable myrosinase activity in vitro and damage-induced breakdown of endogenous GSLs was apparently absent for aliphatic and greatly slowed for indole GSLs (Barth & Jander 2006)