ABSTRACT
This chapter describes the pepsin solubilization of human placenta, bovine kidney cortices, and bovine anterior lens capsule which are three of the tissues most commonly used as a source of basement membrane collagen. Chemical studies concerning the nature of the collagenous components in basement membrane structures, such as glomerular basement membrane, anterior lens capsule, Reicherts membrane, and Descements membrane, suggested that they contained a distinct collagen with the identical polypeptide chains represented by the molecular formular. The chapter describes the purification and characterization of the solubilized native basement membrane pepsin fragments and their component chains. There are two major problems to be considered when isolating basement membrane collagens to use as antigens. First, basement membranes appear to contain more than one collagenous structure, and the relationship between these structures are still unknown. Second, as basement membranes are extremely insoluble, they have to be solubilized using proteolytic enzymes.
