Proteolytic activity of bovine lactoferrin

Maria Teresa Massucci, Francesco Giansanti, Giovanna Di Nino, Manola Turacchio, Maria Federica Giardi, Dario Botti, Rodolfo Ippoliti, Barbara De Giulio, Rosa Siciliano, Giovanna Donnarumma, Piera Valenti, Alessio Bocedi, Fabio Polticelli, Paolo Ascenzi, Giovanni Antonini

Research output: Contribution to journalArticlepeer-review


Bovine lactoferrin catalyzes the hydrolysis of synthetic substrates (i.e., Z-aminoacyl-7-amido-4-metliylcoumarin). Values of Km and k cat for the bovine lactoferrin catalyzed hydrolysis of Z-Phe-Arg-7-amido-4-methylcoumarin are 50 μM and 0.03 s-1, respectively, the optimum pH value is 7.5 at 25°C. The bovine lactoferrin substrate specificity is similar to that of trypsin, while the hydrolysis rate is several orders of magnitude lower than that of trypsin. The bovine lactoferrin catalytic activity is irreversibly inhibited by the serine-protease inhibitors PMSF and Pefabloc. Moreover, both iron-saturation of the protein and LPS addition strongly inhibit the bovine lactoferrin activity. Interestingly, bovine lactoferrin undergoes partial auto-proteolytic cleavage at positions Arg415-Lys 416 and Lys440-Lys441. pKa shift calculations indicate that several Ser residues of bovine lactoferrin display the high nucleophilicity required to potentially catalyze substrate cleavage. However, a definitive identification of the active site awaits further studies.

Original languageEnglish
Pages (from-to)249-255
Number of pages7
Issue number3
Publication statusPublished - Jun 2004


  • Autoproteolysis
  • Iron
  • Lactoferrin
  • LPS

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)


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