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Pancreatic lithostathine as a calcite habit modifier
S Geider1, A Baronnet, C Cerini
1Unité de Recherche de Physiologie et Pathologie Digestives, INSERM U315, 46 Boulevard de la Gaye, 13258 Marseille Cedex 09 France 13009.
The Journal of Biological Chemistry
|October 18, 1996
Summary
Lithostathine, a glycoprotein, prevents pancreatic stones by altering calcite crystal growth. It inhibits calcium carbonate crystal formation, promoting smaller, easily eliminated crystals.
Area of Science:
- Biomineralization
- Crystallography
- Biochemistry
Background:
- Biological fluids are often supersaturated with calcium salts, necessitating mechanisms to prevent pathological crystal formation (lithiasis).
- Pancreatic juice utilizes lithostathine, a glycoprotein, to inhibit calcite crystal growth and prevent lithiasis.
Purpose of the Study:
- To elucidate the interaction mechanism between lithostathine and calcite crystals.
- To understand how lithostathine controls crystal habit and nucleation in pancreatic juice.
Main Methods:
- Scanning electron microscopy (SEM) to visualize crystal morphology.
- Immunochemical localization to identify lithostathine binding sites on crystals.
- Analysis of crystal growth kinetics and calcium ion concentration.
Main Results:
- Lithostathine binding modifies calcite crystal habit from rhombohedral to sub-cubic or olive-shaped.
- Inhibition occurs at crystal face edges, arresting layer spreading and promoting new face formation.
- Increased lithostathine concentration leads to more numerous, smaller crystals and delayed Ca2+ depletion.
Conclusions:
- Lithostathine controls lithogenesis by promoting numerous crystal nuclei and inhibiting calcium ion apposition.
- This mechanism favors the formation of smaller calcite crystals, facilitating their elimination and preventing stone formation.