What characteristic defines globular proteins?

Globular proteins are characterized by their compact, spherical shape, which enables them to be soluble in water. This solubility is crucial for their diverse functions in the body, including acting as enzymes, hormones, and transport molecules. Enzymes, in particular, are a significant class of globular proteins that facilitate biochemical reactions by lowering activation energy. Their structure allows for flexibility and interaction with various substrates, making them vital for many metabolic processes.

The soluble nature of globular proteins contrasts with fibrous proteins, which are typically long, thread-like, and insoluble, serving structural roles in tissues such as collagen and keratin. Therefore, the distinct characteristic of globular proteins being generally soluble and often functioning as enzymes sets them apart within the protein classification.