Effects of Tamm-Horsfall protein and albumin on calcium oxalate crystallization and importance of sialic acids

Mol Urol. Spring 2001;5(1):1-5. doi: 10.1089/109153601750124186.

Abstract

Background: Tamm-Horsfall protein and human serum albumin are common urinary proteins that show uncertain inhibitory action on the crystallization of calcium oxalate monohydrate.

Materials and methods: Batch experiments on crystal nucleation, growth, and aggregation were performed using purified Tamm-Horsfall protein and albumin before and after enzymatic removal of sialic acids from the proteins.

Results: At a concentration of 100 nM, both Tamm-Horsfall protein and albumin promoted the time of crystal nucleation by 18.4% and 8.9%, respectively, relative to the control. However, both of the proteins exerted an inhibitory effect on crystal growth, with the IC(50) being 7.27 nM for Tamm-Horsfall protein and 37.5 nM for albumin. The inhibition of crystal aggregation was 81.82% by Tamm-Horsfall protein 100 nM but only 54.55% at 50 nM after enzymatic removal of the sialic acid. Instead of increasing the inhibition, the effect was changed to promotion after an increase in the concentration of Tamm-Horsfall protein to more than 500 nM for native protein and to more than 100 nM for the enzymatic digest. Albumin showed little change after enzymatic treatment and maintained a maximal inhibitory effect of 72.73% on crystal aggregation when the concentration reached to 100 nM.

Conclusion: Because the promotion of nucleation could lessen the subsequent saturation of a calcium oxalate solution, it is concluded that Tamm-Horsfall protein and albumin show an overall effect of inhibition on crystallization in vitro. The inhibitory effect of Tamm-Horsfall protein is partly related to sialic acid.

MeSH terms

  • Albumins / pharmacology*
  • Calcium Oxalate / chemistry*
  • Calcium Oxalate / urine
  • Chromatography
  • Crystallization
  • Electrophoresis, Polyacrylamide Gel
  • Glycosylation
  • Humans
  • Mucoproteins / pharmacology*
  • Sialic Acids / chemistry*
  • Uromodulin

Substances

  • Albumins
  • Mucoproteins
  • Sialic Acids
  • UMOD protein, human
  • Uromodulin
  • Calcium Oxalate