2. β-Glucuronidase-coupled assays of glucuronoyl esterases
Lucia Fraňová, Vladimír Puchart, Peter Biely Anal Biochem. 2016 Oct 1;510:114-119. doi: 10.1016/j.ab.2016.07.023. Epub 2016 Jul 22.
Glucuronoyl esterases (GEs) are microbial enzymes with potential to cleave the ester bonds between lignin alcohols and xylan-bound 4-O-methyl-d-glucuronic acid in plant cell walls. This activity renders GEs attractive research targets for biotechnological applications. One of the factors impeding the progress in GE research is the lack of suitable substrates. In this work, we report a facile preparation of methyl esters of chromogenic 4-nitrophenyl and 5-bromo-4-chloro-3-indolyl β-D-glucuronides for qualitative and quantitative GE assay coupled with β-glucuronidase as the auxiliary enzyme. The indolyl derivative affording a blue indigo-type product is suitable for rapid and sensitive assay of GE in commercial preparations as well as for high throughput screening of microorganisms and genomic and metagenomic libraries.
3. Thrombin inhibition by the highly selective 'reversible suicide substrate' N-ethoxycarbonyl-D-phenylalanyl-L-prolyl-alpha-azalysine p-nitrophenyl ester
Paolo Ascenzi, Carlo Gallina, Martino Bolognesi Protein Pept Lett. 2005 Jul;12(5):433-8. doi: 10.2174/0929866054395301.
Thrombin is the last enzyme in the blood coagulation cascade. All pharmacological aspects support the use of thrombin inhibitors as antithrombotic agents. Here, we review the unusual inhibition behavior of the highly selective 'reversible suicide substrate' N-ethoxycarbonyl-D-phenylalanyl-L-prolyl-alpha-azalysine p-nitrophenyl ester (Eoc-D-Phe-Pro-azaLys-ONp) targeted to the active center of human alpha-thrombin. Eoc-D-Phe-Pro-azaLys-ONp is an acylating agent, but its hydrolysis product 1(N-ethoxycarbonyl-D-phenylalanyl-L-prolyl)-2(4-aminobutyl) hydrazine behaves as a highly selective human alpha-thrombin competitive inhibitor.
