The porcine sperm motility inhibitor is identical to β-microseminoprotein and is a competitive inhibitor of Na+,K+-ATPase

Chih Fang Chao, Shean Tai Chiou, Hellen Jeng, Wen Chang Chang

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We have isolated a small porcine seminal protein called SMI-1. Our results from peptide sequence, amino acid composition and mass spectral analyses reveal that SMI-1 is identical to porcine β-microseminoprotein, a protein with unknown function. We also report here that this protein inhibits competitively the activity of Na+,K+-ATPase purified from porcine cerebral cortex in a dose-dependent manner. The inhibitory effect could be reversed by the addition of ATP. The half-maximal inhibition was achieved at an inhibitor concentration of 90 μM.

Original languageEnglish
Pages (from-to)623-628
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number2
Publication statusPublished - Jan 17 1996


ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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