4.A.6.1.19
PTS uptake system for glucoselysine and fructoselysine, GfrABCD (Miller et al. 2015).  Two glycases, GfrE and GfrF, are requred for the utilization of these two compounds for growth, respectively, and GfrF was shown to hydrolyze fructoselysine-6-P to lysine and fructose-6-P.  Expression of the operon, gfrABCDEF, is regulated by a transcriptional activator, GfrR and sigma factor RpoN (Miller et al. 2015).  GfrD affects proteolytic processing, a necessary but insufficient step for CadC activation, rendering CadC able to activate target genes involved in lysine metabolism (Lee et al. 2013).