Estimating kinetic constants in the Michaelis-Menten model from one enzymatic assay using Approximate Bayesian Computation

The Michaelis-Menten equation is one of the most extensively used models in biochemistry for studying enzyme kinetics. However, this model requires at least a couple (e.g., eight or more) of measurements at different substrate concentrations to determine kinetic parameters. Here, we report the discovery of a novel tool for calculating kinetic constants in the Michaelis-Menten equation from only a single enzymatic assay. As a consequence, our method leads to reduced costs and time, primarily by lowering the amount of enzymes, since their isolation, storage and usage can be challenging when conducting research

Azo dyes – biological activity and synthetic strategy

Barwniki azowe stanowią najważniejszą i najliczniejszą grupę syntetycznych barwników o pełnej palecie barw. Związki te zawierają ugrupowanie –N=N– jako charakterystyczny chromofor, a otrzymuje się je głównie w reakcji diazowania i sprzęgania. Stanowią one ok. 60% wszystkich barwników stosowanych w przemyśle spożywczym i tekstylnym. Obok właściwości barwiących, znana jest ich aktywność biologiczna, stanowiąca zagrożenie dla człowieka i środowiska, ale mająca również potencjał farmakologiczny. W artykule zaprezentowano wybrane aspekty aktywności biologicznej tytułowych związków w kontekście zastosowań medycznych oraz toksyczności, a także nowoczesne metody syntezy.Presented are outlines of the R&D policy of the Institute of Biopolymers and Chemical Fibres in the light of future activities directed toward the enhancement of cooperation between R&Dand business units. The Institute’s strategic BIO-NANO-TECHNO domain is highlighted

Discovery of potent and selective inhibitors of human aminopeptidases ERAP1 and ERAP2 by screening libraries of phosphorus-containing amino acid and dipeptide analogues

A collection of fifty phosphonic and phosphinic acids was screened for inhibition of ERAP1 and ERAP2, the human endoplasmic reticulum aminopeptidases. The cooperative action of these enzymes is manifested by trimming a variety of antigenic precursors to be presented on the cell surface by major histocompatibility class I. The SAR studies revealed several potent compounds, particularly among the phosphinic dipeptide analogues, that were strong inhibitors of ERAP2 (Ki = 100–350 nM). A wide structural diversity of the applied organophosphorus compounds, predominantly non-proteinogenic analogues, allowed identification of representatives selective toward only one form of ERAP. For example, N′-substituted α,β-diaminophosphonates and phosphinates exhibited potency only toward ERAP2, which is in agreement with the P1 basic substrate-oriented specificity. Such discriminating ligands are invaluable tools for elucidating the precise role of a particular aminopeptidase in the concerted function of antigen processing and in human diseases. © 2016 Elsevier Lt

Neutral metalloaminopeptidases APN and MetAP2 as newly discovered anticancer molecular targets of actinomycin D and its simple analogs

The potent transcription inhibitor Actinomycin D is used with several cancers. Here, we report the discovery that this naturally occurring antibiotic inhibits two human neutral aminopeptidases, the cell-surface alanine aminopeptidase and intracellular methionine aminopeptidase type 2. These metallo-containing exopeptidases participate in tumor cell expansion and motility and are targets for anticancer therapies. We show that the peptide portions of Actinomycin D and Actinomycin X2 are not required for effective inhibition, but the loss of these regions changes the mechanism of interaction. Two structurally less complex Actinomycin D analogs containing the phenoxazone chromophores, Questiomycin A and Actinocin, appear to be competitive inhibitors of both aminopeptidases, with potencies similar to the non-competitive macrocyclic parent compound (Ki in the micromolar range). The mode of action for all four compounds and both enzymes was demonstrated by molecular modeling and docking in the corresponding active sites. This knowledge gives new perspectives to Actinomycin D’s action on tumors and suggests new avenues and molecules for medical applications