OptiCol™ Human Collagen Type IV is the primary collagen found in the extracellular basement membranes separating a variety of epithelial and endothelial cells. It is a major component of the dermal-epidermal junction where it is mostly found in the lamina densa. It is a heterotrimeric molecule containing two α1-like and one α2-like chains. This Type IV collagen is isolated from human placenta and is purified using a multi-step process.