Inhibitory effect of calcium phosphate-associated proteins on calcium oxalate crystallization: alpha2-HS-glycoprotein, prothrombin-F1 and osteopontin.
OBJECTIVE
To analyse urinary calcium phosphate- associated proteins and assess their inhibitory effects on calcium oxalate crystallization. Materials and methods Urine samples were collected over 24 h from five healthy men and calcium phosphate crystallization induced with NaOH solution. The bound proteins were separated on a cellulose column. To examine the effect of urinary calcium phosphate-associated proteins on calcium oxalate crystallization, 60 L of urine was collected from the healthy men. The effect of the separated fractions was studied in a mixed suspension/mixed product removal system.


RESULTS
The separated proteins were identified as alpha2-HS-glycoprotein, prothrombin fragment 1 and osteopontin. Prothrombin fragment 1 and osteopontin strongly inhibited the growth of calcium oxalate crystals in artificial urine.


CONCLUSIONS
alpha2-HS-glycoprotein, prothrombin fragment 1 and osteopontin selectively bound with calcium phosphate crystals in urine. Prothrombin fragment 1 and osteopontin in urine may strongly influence stone formation.
Nishio
S
S
Department of Urology, Ehime University School of Medicine, Shigenobu, Ehime, Japan. nishio@m.ehime-u.ac.jp
Iseda
T
T
Takeda
H
H
Iwata
H
H
Yokoyama
M
M
D000328:Adult; D001798:Blood Proteins / Q000652:urine*; D002129:Calcium Oxalate / Q000037:antagonists & inhibitors*; D002130:Calcium Phosphates / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003460:Crystallization; D006801:Humans; D008297:Male; D008875:Middle Aged; D053495:Osteopontin; D010446:Peptide Fragments / Q000652:urine*; D011516:Prothrombin / Q000652:urine*; D012795:Sialoglycoproteins / Q000652:urine*; D060749:alpha-2-HS-Glycoprotein
C556354:AHSG protein, human; D001798:Blood Proteins; D002130:Calcium Phosphates; D010446:Peptide Fragments; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D060749:alpha-2-HS-Glycoprotein; C485828:alpha-tricalcium phosphate; C045879:prothrombin fragment 1.2; C485830:tetracalcium phosphate; D053495:Osteopontin; D002129:Calcium Oxalate; C485838:calcium phosphate, monobasic, anhydrous; D011516:Prothrombin; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous