title: Purification and characterization of a 31 kDa mycobacterial excretory-secretory antigenic protein with a diagnostic potential in pulmonary tuberculosis.
abstract: Proteins secreted into the culture medium by Mycobacterium tuberculosis are shown to be a source of antigens of immunodiagnostic importance. In our earlier study, we had reported a 31-37 kDa seroreactive gel-eluted antigenic fraction (ESAS-7), isolated from culture filtrate proteins of Mycobacterium tuberculosis H37Ra. In this report, we describe further purification of excretory-secretory ESAS-7 antigen fraction by fast protein liquid chromatography (FPLC) on Resource 'S' cation-exchange column and isolation of a more active and purified protein antigen fraction ESAS-7F. ESAS-7F antigen was characterized as a 31 kDa molecular weight glycoprotein containing a metallo-serine protease activity. N-terminal sequence analysis showed the first five amino acids as NTGQS (Asp-Thr-Gly-Glu-Ser). The present study helped in the isolation of a well characterized 31 kDa mycobacterial glycoprotein antigen with protease activity and diagnostic potential in detection of tuberculosis infection.
authors.affiliation: Jamnalal Bajaj Tropical Disease Research Centre and Department of Biochemistry, Mahatma Gandhi Institute of Medical Sciences, Wardha, Maharashtra, India.
authors.forename: E R
authors.initials: ER
authors.lastname: Nair
authors.forename: S
authors.initials: S
authors.lastname: Banerjee
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: M V
authors.initials: MV
authors.lastname: Reddy
authors.forename: B C
authors.initials: BC
authors.lastname: Harinath
mesh_terms: D000942:Antigens, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods; D006801:Humans; D066298:In Vitro Techniques; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D020539:Sequence Analysis, Protein; D014397:Tuberculosis, Pulmonary / Q000097:blood* / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins