Mature bovine lenses contain 75-100 muM of a previously unidentified nucleoside polyphosphate. Using P-31 NMR spectroscopy we have identified this compound as diadenosine-5',5"'-triphosphate. The accumulation of this compound,in the lens may be a consequence of the high levels of activities of t-RNA synthetases during lens differentiation and growth. The function, if any, of this compound in the bovine lenses is presently unknown. (C) 2004 Elsevier Inc. All rights reserved.