When either pure form is dissolved in water, an equilibration takes place which results in a gradual change in the specific rotation. This phenomenon is known as 11 . In disaccharides, two simple sugars are linked together by an acetal bond. Amino acids exist primarily in the form of a dipolar ion called a 20 . Proteins may be classified into two major types according to their composition.
Simple proteins yield only amino acids on hydrolysis.
21 proteins yield other compounds in addition to amino acids. Another way to classify proteins is as either 22 or globular. Structurally, proteins have primary, secondary and tertiary structures. The primary structure is the 23 in which the amino acids are bound together. There are two major types of secondary structure.