In muscle, parvalbumin is thought to be involved in relaxation after contraction. It binds two calcium ions. Muscle (at protein level). Causes an allergic reaction in human. Binds to IgE in all 28 patients tested allergic to fish. IgE-binding is greatly reduced by treatment with periodate indicating the presence of carbohydrate-containing epitopes. Calcium depletion results in more than 50% reduction in IgE-binding in 9 patients out of 14 tested. Assays performed under reducing conditions do not affect IgE-binding. This parvalbumin has an isoelectric point of 4.40. Belongs to the parvalbumin family.