| 17888672 |
Oliveira AS, Migliolo L, Aquino RO, Ribeiro JK, Macedo LL, Andrade LB, Bemquerer MP, Santos EA, Kiyota S, de Sales MP: Purification and characterization of a trypsin-papain inhibitor from Pithecelobium dumosum seeds and its in vitro effects towards digestive enzymes from insect pests. Plant Physiol Biochem. 2007 Oct-Nov;45(10-11):858-65. Epub 2007 Aug 11.
A novel trypsin-papain inhibitor, named PdKI-2, was purified from the seeds of Pithecelobium dumosum seeds by TCA precipitation, Trypsin-Sepharose chromatography and reversed-phase HPLC. PdKI-2 had an M (r) of 18.1 kDa as determined by SDS-PAGE and was composed of a single polypeptide chain. The inhibition on trypsin was stable at pH range 2-10, temperature of 50 degrees C and had a K (i) value of 1.65 x 10 (-8) M, with a competitive inhibition mechanism. PdKI-2 was also active to papain, a cysteine proteinase, and showed a noncompetitive inhibition mechanism and K (i) value of 5.1 x 10 (-7) M. PdKI-2 was effective against digestive proteinase from bruchids Zabrotes subfasciatus and Callosobruchus maculatus; Dipteran Ceratitis capitata; Lepidopterans Plodia interpunctella and Alabama argillacea, with 74.5%, 70.0%, 70.3%, 48.7%, and 13.6% inhibition, respectively. Results support that PdKI-2 is a member of Kunitz-inhibitor family and its effect on digestive enzyme larvae from diverse orders indicated this protein as a potent insect antifeedant. |
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