small molecule binding
   |__ion binding
       |__cation binding  1108 rec.
           |__acetylcholine binding 1 rec.
           |__ammonium ion binding
           |__AMP binding 4 rec.
           |__arginine binding
           |__chitosan binding
           |__choline binding
           |__cocaine binding 1 rec.
           |__dopamine binding
           |__epinephrine binding
           |__glycine binding 1 rec.
           |__histamine binding
           |__L-cysteine binding
           |__L-glutamine binding 1 rec.
           |__L-leucine binding 1 rec.
           |__L-tyrosine binding
           |__metal ion binding 1079 rec.
           |   |__alkali metal ion binding(+) 6 rec.
           |   |__calcium ion binding(+) 204 rec.
           |   |__lead ion binding
           |   |__magnesium ion binding 48 rec.
           |   |__metal chelating activity
           |   |__transition metal ion binding(+) 743 rec.
           |__norepinephrine binding
           |__phosphatidylcholine binding 5 rec.
           |__proton binding
           |__putrescine binding
           |__pyridoxal binding
           |__pyridoxamine binding
           |__S-adenosyl-L-methionine binding 4 rec.
           |__serine binding
           |__serotonin binding 2 rec.
           |__spermidine binding
           |__thiamine binding 1 rec.
           |__thiamine pyrophosphate binding 5 rec.
           |__tryptophan binding