%0 Journal Article
%T Purification and structural stability of a trypsin inhibitor from Amazon Inga cylindrica [Vell.] Mart. seeds
%A Calderon
%A Leonardo A
%A Almeida Filho
%A Humberto A
%A Teles
%A Rozeni C. L
%A Medrano
%A Francisco J
%A Bloch Jr
%A Carlos
%A Santoro
%A Marcelo M
%A Freitas
%A Sonia M
%J Brazilian Journal of Plant Physiology
%D 2010
%I Scientific Electronic Library Online
%R 10.1590/S1677-04202010000200001
%X inga cylindrica trypsin inhibitor (icti) was purified as a single polypeptide chain by one step anion-exchange chromatography from a crude extract of inga cylindrica (vell.) mart. seeds. icti is a 19.5 kda protein presenting a remarkable inhibitory activity against bovine trypsin (ec 3.4.21.4) (ki = 4.3 nm). circular dichroism analysis revealed that this inhibitor is a ¦Â type protein (40.4% of ¦Â-strand; 24.6% of ¦Â-turn and 6.7% of ¦Á-helix) in accordance with properties displayed in kunitz type inhibitors. icti is a thermal stable protein within a wide range of ph (1.6 to 10.0) exhibiting highest stability at ph 7.0 as indicated by tm of 70.0 oc and ¦Äg25 of 48.5 ¡À 0.7 kj.mol-1. the values of ¦Äg25 at ph 1.6 (22.5 ¡À 1.2 kj.mol-1) and ph 10.0 (31.5 ¡À 1.0 kj.mol-1) indicate a reduced structural stability of the protein under these conditions. this is likely to result from pka differences of the acid and basic side chains reflecting the changes in the non-covalent interactions in the folded state.
%K inga cylindrica [vell.] mart
%K leguminosae
%K mimosoideae
%K protease inhibitor
%K protein stability
%K trypsin inhibitor.
%U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S1677-04202010000200001&lng=en&nrm=iso&tlng=en