Synonyms: Collagen, Type IV, Human Placenta; collagen type I from rat tail; Collagen from rat tail; Collagen, Type II, Bovine Joint Cartilage;Collagens polypeptide; Collagen from human placenta; Collagen, Type V, Human Placenta; Collagen calf skin; Collagen, Type II, Mouse Sternum Cartilage;collagen type I from calf skin;