Biochemical characterization of Acacia schweinfurthii serine proteinase inhibitor

Frank Odei-Addo, Carminita Frost, Nanette Smith, Tomohisa Ogawa, Koji Muramoto, Maria Luiza Vilela Oliva, László Gráf, Ryno Naude

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


One of the many control mechanisms of serine proteinases is their specific inhibition by protein proteinase inhibitors. An extract of Acacia schweinfurthii was screened for potential serine proteinase inhibition. It was successfully purified to homogeneity by precipitating with 80% (v/v) acetone and sequential chromatographic steps, including ion-exchange, affinity purification and reversed-phase high performance liquid chromatography. Reducing sodium dodecyl sulphate polyacrylamide gel electrophoresis conditions revealed an inhibitor (ASTI) consisting of two polypeptide chains A and B of approximate molecular weights of 16 and 10kDa, respectively, and under non-reducing conditions, 26kDa was observed. The inhibitor was shown to inhibit bovine trypsin (Ki of 3.45nM) at an approximate molar ratio of inhibitor:trypsin (1:1). The A- and B-chains revealed complete sequences of 140 and 40 amino acid residues, respectively. Sequence similarity (70%) was reported between ASTI A-chain and ACTI A-chain (Acacia confusa) using ClustalW. The B-chain produced a 76% sequence similarity between ASTI and Leucaena leucocephala trypsin inhibitor.

Original languageEnglish
Pages (from-to)633-638
Number of pages6
JournalJournal of Enzyme Inhibition and Medicinal Chemistry
Issue number5
Publication statusPublished - 2014 Oct 1


  • Acacia schweinfurthii
  • Amino acid sequence
  • Proteinase inhibitors
  • Trypsin inhibitor


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