title: JcTI-I: a novel trypsin inhibitor from Jatropha curcas seed cake with potential for bacterial infection treatment.
abstract: Jatropha curcas seed cake is a low-value by-product resulting from biodiesel production. The seed cake is highly toxic, but it has great potential for biotechnology applications as it is a repository of biomolecules that could be important in agriculture, medicine, and industry. To explore this potential, a novel trypsin inhibitor called JcTI-I was purified by fractionation of the crude extract with trichloroacetic acid (2.5%, v/v) followed by affinity chromatography (Trypsin-Sepharose 4B) and molecular exclusion (Sephacryl S-200). Non-reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration showed that JcTI-I has approximately 20.0~kDa. Mass spectrometry analysis revealed that the intact molecular mass of JcTI-I is 10.252~kDa. Moreover, JcTI-I is a glycoprotein with 6.4% (m/m) carbohydrates, pI of 6.6, N-terminal sequence similarity around 60% to plant albumins and high stability to heat, pH, and salinity. JcTI-I presented antibacterial activity against the human pathogenic bacteria Salmonella enterica subspecies enterica serovar choleraesuis and Staphylococcus aureus, with minimum inhibitory concentration less than 5~μg/mL. Furthermore, JcTI-I did have inhibitory activity against the serine proteases from the tested bacteria. Otherwise, no hemolytic activity of human erythrocytes and signs of acute toxicity to mice were observed for JcTI-I. The results demonstrate the benefits of J. curcas seed cake as a source of trypsin inhibitor with potential for biotechnological application as a new antimicrobial agent against human pathogenic bacteria.
authors: Laboratory of Plant Toxins, Department of Biochemistry and Molecular Biology, Federal University of Ceara Fortaleza, Brazil.
authors: Helen P S
authors: HP
authors: Costa
authors: Laboratory of Plant Toxins, Department of Biochemistry and Molecular Biology, Federal University of Ceara Fortaleza, Brazil.
authors: Jose T A
authors: JT
authors: Oliveira
authors: Laboratory of Plant Toxins, Department of Biochemistry and Molecular Biology, Federal University of Ceara Fortaleza, Brazil.
authors: Daniele O B
authors: DO
authors: Sousa
authors: Laboratory of Plant Toxins, Department of Biochemistry and Molecular Biology, Federal University of Ceara Fortaleza, Brazil.
authors: Janne K S
authors: JK
authors: Morais
authors: School of Pharmacy, University of Fortaleza Fortaleza, Brazil.
authors: Frederico B
authors: FB
authors: Moreno
authors: School of Pharmacy, University of Fortaleza Fortaleza, Brazil.
authors: Ana Cristina O
authors: AC
authors: Monteiro-Moreira
authors: Department of Forestry Engineering, Federal University of Campina Grande Patos, Brazil.
authors: Ricardo A
authors: RA
authors: Viegas
authors: Laboratory of Plant Toxins, Department of Biochemistry and Molecular Biology, Federal University of Ceara Fortaleza, Brazil.
authors: Ilka M
authors: IM
authors: Vasconcelos
keywords: Jatropha curcas; bacterial infections, antimicrobial agent; seed cake; serine proteinase inhibitor; trypsin inhibitor