Collagen and Skin Structure

Abstract

In order to understand the principles that underpin the conversion of hide or skin to leather, it is necessary to know the fundamental structure of the raw material and how that structure might be modified chemically. The chemistry of collagen defines not only the sequencing of its amino acid constituents but also the physical nature of its structure and how it creates levels of structure or a hierarchy. This depends on the chains creating a triple helix as the basic unit of structure. The chemical properties of collagen are defined by the sidechains on the helices, which may be charged, depending on the pH; in this way, collagen can undergo a wide range of covalent or electrostatic reactions, which are the basis for tanning processes. At the heart of the chemistry of collagen is the relationship with water, which is an integral feature of structure: the supramolecular matrix of water around the triple helices provides the region for chemical modification, leading to tanning technology.