ABSTRACT
Some proteins have long parallel chains with multiple cross-links. These are the fibrous proteins, e.g. collagen in cartilage, keratin in hair, actin and myosin in muscle. Most proteins are, however, globular and these form all enzymes and some hormones. Their functions depend on the precise shape of the protein molecule. If a globular protein is heated or treated with strong acid or alkali, the hydrogen bonds are broken and it becomes more fibrous, a process known as denaturation.
