The role of Thr284 in the catalysis of Cathepsin E
Abstract：Objective To investigate the role of Thr284 in the catalysis of Cathepsin E.Methods Replace Thr284 with a serine to produce a T284S mutant by site-directed mutagenesis.Results Both wild type and mutant are expressed and present in the HEK 293T cell culture media and cell lysate. Mutant is still able to auto activate, although its activity is only 40% of that of wild type. The Km value of mutant is similar to that of wild type, but its Kcat value is smaller than that of wild type. Both mutant and wild type are inhibited by pepstatin and Ascaris pepsin inhibitor with similar Ki values. The CD spectra of mutant and wild type is similar.Conclusion (1)Thr284 is very important to the catalytic activity. The mutant causes change of hydrogen bonds distribution and thus lowers the hydrolysis efficiency. (2)Other protein structural features of BACE-1 than its carboxyl motif may contribute to its insensitivity to pepstatin.
Keywords：Active site motifAspartic proteinaseCathepsin EMutant analysis
Publication Date：2009-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 661-665 )