Resilin

Literature References: Highly amorphous rubberlike protein found in insect cuticle. Isoln and characterization: Weis-Fogh, J. Exp. Biol. 37, 889 (1960). The structure is a cross-linked random network of flexible protein chains, incorporating 15 of the more common amino acids and involving covalent bonds. Cross-links have been identified as di- and trityrosine. Biosynthesis: Coles, J. Insect Physiol. 12, 679 (1966). Similar to elastin, q.v., but does not form fibers; occurs as masses or typically as 2-5 m layers. Elasticity approaches that of the ideal cross-linked rubber. Responsible for various springlike actions of winged insects. In flea: Rothschild, Nature 239, 45 (1972). Review: Andersen, Acta Physiol. Scand. 66, Suppl. 263 (1966); idem, "Resilin" in Comprehensive Biochemistry vol. 26C, M. Florkin, E. H. Stotz, Eds. (Elsevier, New York, 1971) pp 633-657.

Properties: The colorless material is insol in water <140° and in all other solvents not rupturing peptide bonds. Swells in water and protein solvents; shrinks and becomes hard in absolute methanol, ethanol, dioxane, acetone. Shows no tendency to crystallize at all. Fluorescent in uv light.