Which of the following enzymes is classified as a lyase?

Explanation

Lyases are enzymes that catalyze the breaking of various chemical bonds by means other than hydrolysis and oxidation. Among the options, fumarase is a classic example of a lyase, as it catalyzes the reversible hydration of fumarate to malate. The other enzymes belong to different classes: glutamine synthetase is a ligase, cholinesterase is a hydrolase, and amylase is also a hydrolase.