title: Purification and physicochemical characterization of a trypsin inhibitor from Cassia absus Linn.
abstract: A thermotolerant protein with trypsin inhibitory activity designated as CaTI was purified to homogeneity from seeds of Cassia absus. Gel filtration chromatography and SDS-PAGE analysis showed the apparent molecular mass of ~20 kDa. Partial internal sequences indicate that CaTI belongs to Kunitz-inhibitor family. CaTI inhibits the bovine trypsin in 1:1 molar ratio and exhibited a competitive-type inhibitory activity with Ki = 5.6 x 10(-9) M. The inhibitory activity was retained over a broad pH range (2-12). Thermal stability study showed that it is stable up to 80 °C and inhibition activity reduced at and above 90 °C which might be due to the presence of predominantly β-sheets revealed by the CD study. The proteolysis studies of CaTI exhibited strong resistance to proteolysis by different proteases tested. The studies show that CaTI can be used as potential candidates for the development of the transgenic plant against the microbes and insect pests.
authors.forename: Girijesh K
authors.initials: GK
authors.lastname: Patel
authors.forename: Amit K
authors.initials: AK
authors.lastname: Gupta
authors.forename: Akshita
authors.initials: A
authors.lastname: Gupta
authors.forename: Manisha
authors.initials: M
authors.lastname: Mishra
authors.forename: Pradhyumna K
authors.initials: PK
authors.lastname: Singh
authors.forename: Anil K
authors.initials: AK
authors.lastname: Saxena
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee-247 667, India. aksbsfbs@yahoo.co.in.
authors.forename: Ashwani K
authors.initials: AK
authors.lastname: Sharma
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002366:Cassia / Q000737:chemistry*; D002417:Cattle; D055598:Chemical Phenomena; D006863:Hydrogen-Ion Concentration; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D014357:Trypsin / Q000378:metabolism*; D014361:Trypsin Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D010940:Plant Proteins; D014361:Trypsin Inhibitors; D014357:Trypsin