English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The prohormone-processing Kex2 protease of the budding yeast Saccharomyces cerevisiae can be converted from an intracellular membrane protein to a soluble, secreted, and active form by deletion of the transmembrane domain and C-terminal tail. One such molecule was purified to near homogeneity from the culture medium of an overexpressing yeast strain. Amino acid sequence analysis revealed that the N terminus of mature Kex2 protease is created by a potentially autoproteolytic cleavage at Lys108-Arg109, prior to the domain homologous to subtilisin, followed by trimming of Leu-Pro and Val-Pro dipeptides by the Ste13 dipeptidyl aminopeptidase. Kinetic parameters were examined using fluorogenic peptidyl-methylcoumarin amide substrates. Initial burst titration indicated that the preparation was entirely active. Measurements of dependence of activity on pH yielded a simple curve suggesting titration of a single ionizable group. Activity was half-maximal at pH 5.7 and nearly constant from pH 6.5 to 9.5. Discrimination between substrates was as great as 360-fold in Km and 130-fold in kcat. Substrates with a Lys-Arg dipeptide preceding the cleaved bond were preferred, having kcat/Km values up to 1.1 x 10(7) sec-1.M-1. The enzyme cleaved substrates having Arg-Arg, Pro-Arg, Ala-Arg, and Thr-Arg with increased Km but with unchanged kcat. In contrast, the enzyme displayed a dramatically lower kcat for a Lys-Lys substrate with a smaller increase in Km. Thus the two residues preceding the cleaved bond may play distinct roles in the selectivity of binding and cleavage of prohormone substrates.

Structural and enzymatic characterization of a purified prohormone-processing enzyme: secreted, soluble Kex2 protease.