A hormone dependent calcium-binding protein in the mantle edge of the freshwater snail Lymnaea stagnalis.

By means of gel filtration and ion exchange chromatography on calcium-saturated Chelex-100, a calcium-binding fraction was isolated from the mantle edge of the freshwater snail lymnaea stagnalis. This fraction was not present in other tissues. Treatment with trypsin caused a disappearance of the calcium-binding capacity, proving that the active substance in this fraction is a protein (calcium-binding protein; CaBP). Removal of the growth hormone-producing neuroendocrine light green cells resulted in a strong decrease of the amount of CaBP. It is concluded that L. stagnalis possesses a hormone-dependent CaBP, probably responsible for the maintenance of a high calcium concentration in that part of the mantle that produces the outer crystalline layer of the shell.