Which one of the following is an enzyme ?

Trypsin is a proteolytic enzyme secreted by the pancreas in an inactive form called trypsinogen. It is activated in the small intestine, where it functions as a serine protease to break down proteins into amino acids [2]. In contrast, the other options are hormones. Glucagon and insulin are peptide hormones produced by the alpha and beta cells of the pancreatic islets of Langerhans, respectively, to regulate blood glucose levels [3]. Somatotropin, also known as growth hormone, is a protein hormone secreted by the pituitary gland that regulates somatic growth and substrate metabolism [4]. While enzymes like trypsin act as biological catalysts for chemical reactions (such as digestion), hormones like insulin and glucagon act as chemical messengers to coordinate physiological processes [4]. Therefore, trypsin is the only enzyme among the provided choices.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > Activity 5.3 > p. 86
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > Do You Know? > p. 111
3. [3] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > Do You Know? > p. 110
4. [4] https://pmc.ncbi.nlm.nih.gov/articles/PMC5642081/