Which of the following proteins acts as a messenger in living system?

Which among the following enzymes hydrolyzes $ \text{starch}$?

The function of enzymes in the living system is to

Which of the following biomolecules acts as specific catalysts in biological reactions?

Insulin production and its action in the human body are responsible for the level of diabetes. This compound belongs to which of the following categories?

Which of the following enzymes is not useful in the digestion of proteins?