[Pancreatic lithostathine inhibitor of calcium carbonate precipitation: structure-function relationship].
Pancreatic juice is naturally supersatured in calcium and bicarbonate ions. A mechanism controlling CaCO3 crystal formation and growth is therefore necessary to prevent duct clogging. Lithostathine, a glycoprotein synthesized by acinar cells and secreted in pancreatic juice, could be involved in such a control. Lithostathine significantly delayed crystal nucleation and inhibited growth of CaCO3 crystals from supersatured solutions. Lithostathine adsorbed to sites specifically inhibiting crystal growth with a dissociation constant Kd = 0.9 x 10(-6) mol/L. The glycosylated N-terminal undecapeptide generated by limited trypsin hydrolysis of lithostathine, inhibited CaCO3 crystal growth with a Kd = 3.4 x 10(-6) mol/L similar to that of lithostathine. On the contrary, the carboxy-terminal polypeptide (lithostathine H) was inactive. The N-terminal undecapeptide of lithostathine is therefore essential to the inhibitory activity of the protein on CaCO3 crystal growth.
Bernard
J P
JP
INSERM U315, Marseille.
Takacs
T
T
de Reggi
M
M
Sarles
H
H
Dagorn
J C
JC
D000327:Adsorption; D000595:Amino Acid Sequence; D002119:Calcium Carbonate / Q000737:chemistry*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000494:pharmacology*; D003460:Crystallization; D006801:Humans; D051847:Lithostathine; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins; D010179:Pancreas / Q000737:chemistry*; D013329:Structure-Activity Relationship; D014357:Trypsin / Q000378:metabolism
D002135:Calcium-Binding Proteins; D051847:Lithostathine; D009419:Nerve Tissue Proteins; C497617:REG1A protein, human; D014357:Trypsin; D002119:Calcium Carbonate
La lithostathine pancréatique inhibiteur de la précipitation du CaCO3: relations structure-fonction.