T^he present study entails with the role of amino acids in the ■*- mineralogical and chemical composition of some bivalve and gastropod shells. The common skeletal minerals reported for the studied shells were found to be aragonite, calcite, and Mg-calcite. The bivalve Tridacna elongata showed high level of calcite and low level of aspartic the acid. Aragonite recorded high levels in the other examined species.Glycine, isoleucine and proline represented the extreme higher values among the neutral amino acids in all examined shells. The neutral amino acids can be quantitatively arranged in the following order; Glycine > Isoleucine > Proline >Alanine > Leucine > Valine> Serine > Threonine.
The chemical study of the investigated shells indicates that, copper recorded its maximum value (33 p-gg'1) in the bivalve Tridacna elongata and its minimum (12 jagg"1) in the gastropod Conus coronatus. The maximum values of zinc, lead, iron and manganese were recorded in bivalve Acanthocardium aculeata whereas, the studied gastropods revealed lower values for these elements. This trend of the element distribution was observed also for calc'um and magnesium. Acidic amino acids seem to play an impcuint role in fixation of calcium, nucleation of CaC03 and growtf of the mineral phase.