Wikipedia
DARPins (an acronym for designed ankyrin repeat proteins) are genetically engineered antibody mimetic proteins typically exhibiting highly specific and high-affinity target protein binding. They are derived from natural ankyrin proteins, one of the most common classes of binding proteins in nature, which are responsible for diverse functions such as cell signaling, regulation and structural integrity of the cell. DARPins consist of at least three, repeat motifs proteins, and usually consist of four or five. Their molecular mass is about 14 or 18 kDa ( kilodaltons) for four- or five-repeat DARPins, respectively.
DARPins constitute a new class of potent, specific and versatile small-protein therapies, and are used as investigational tools in various research, diagnostic and therapeutic applications. Molecular Partners AG, a clinical-stage biopharmaceutical company that is investigating these molecules, has several DARPin molecules in clinical and preclinical development.