Why is olive oil used as a substrate in the reference method for lipase?

Olive oil serves as a substrate in the reference method for lipase because it consists primarily of triglycerides, which are specifically the type of lipids that lipase enzymes act upon. Using olive oil helps ensure that the measurement of lipase activity is specific and accurate, as the enzyme is designed to hydrolyze triglycerides into fatty acids and glycerol.

The choice related to other esterases potentially hydrolyzing triglycerides and synthetic diglycerides is particularly relevant because using a natural substrate like olive oil minimizes the risk of interference from other enzymes. This specificity is crucial for obtaining reliable results, as it isolates the activity of lipase without the complication of other esterases influencing the outcome.

In contrast, while the other options touch on different aspects of enzymology, they do not capture the primary reason for selecting olive oil as a substrate. Coupled reactions involving NADH, solubility issues with synthetic substrates, or product inhibition from triglycerides don’t fully explain why olive oil is the preferred substrate in this context, particularly when considering the focus on the accurate evaluation of lipase activity.