In which one of the following sets of three items each belong to the category mentioned against them?
(a) Lysine, glycine, thiamine - amino acids
(b) Myosin, oxytocin and gastrin -hormones
(c) Rennin, helicase and hyaluronidase - enzymes
(d) Optic nerve, oculomotor, vagus - sensory nerves
(c) Rennin, helicase, hyaluronidase are all enzymes. Rennin (chymosin) secreted by stomach is responsible for clotting milk. It acts on a soluble milk protein (caseinogen) to convert it into insoluble form (casein). Helicase unwinds double-stranded helical DNA during replication. Hyaluronidase is able to digest hyaluronic acid (major glycosaminoglycan) and is therefore important in modulating the removal of cell matrix in order to facilitate cell movemnt or tissue organization. Thiamine is not an amino acid, it is vitamin B1, which is active in the form of thiamin pyrophosphate, a coenzyme in decarboxylation reactions in carbohydrate metabolism. A deficiency of vitamin B1 leads to beri beri. Myosin is a contractile protein found in eukaryotic tissue, interacts with actin to bring about contraction of muscle or cell movement. Among optic, oculomotor and vagus, which are cranial nerves, optic is sensory in nature, oculomotor is motor and vagus is mixed sensory nerves.