Control peptides are inactive analogs of bioactive peptides for obtaining negatives. Usually, scrambled, reverted or analogous peptides are used as controls, e.g.
Amyloid β-Protein (1-42)  Amyloid β-Protein (42-1)
RGDS  RGES
Prion Protein (106-126) (human)  Prion Protein (106-126) (human) (scrambled)