Screening of in Vitro Inhibition of Lactoperoxidase Enzyme by Methyl Benzoate Derivatives with Molecular Docking Studies.

Lactoperoxidase enzyme (LPO) is secreted from salivary, mammary, and other mucosal glands including the bronchi, lungs, and nose, which had functions as a natural and the first line of defense towards viruses and bacteria. In this study, methyl benzoates were examined in LPO enzyme activity. Methyl benzoates are used as precursors in the synthesis of aminobenzohydrazides used as LPO inhibitors. For this purpose, LPO was purified in a single step using sepharose-4B-l-tyrosine-sulfanilamide affinity gel chromatography with a yield of 9.91 % from cow milk. Also, some inhibition parameters including the half maximal inhibitory concentration (IC50 ) value and an inhibition constant (Ki ) values of methyl benzoates were determined. These compounds inhibited LPO with Ki values ranging from 0.033±0.004 to 1540.011±460.020 µM. Compound 1 a (methyl 2-amino-3-bromobenzoate) showed the best inhibition (Ki =0.033±0.004 µM). The most potent inhibitor (1 a) showed with a docking score of -3.36 kcal/mol and an MM-GBSA value of -25.05 kcal/mol, of these methyl benzoate derivatives (1 a-16 a) series are established H-bond within the binding cavity with residues Asp108 (distance of 1.79 Å), Ala114 (distance of 2.64 Å), and His351 (distance of 2.12 Å).

Affinity-based and in a single step purification of recombinant horseradish peroxidase A2A isoenzyme produced by Pichia pastoris.

Horseradish peroxidase (HRP) is an oxidoreductase enzyme and oxidizes various inorganic and organic compounds. It has wide application areas such as immunological tests, probe-based test techniques, removal of phenolic pollutants from wastewater and organic synthesis. HRP is found in the root of the horseradish plant as a mixture of different isoenzymes, and it is very difficult to separate these enzymes from each other. In this regard, recombinant production is a very advantageous method in terms of producing the desired isoenzyme. This study was performed to produce HRP A2A isoenzyme extracellularly in Pichia pastoris and to purify this enzyme in a single step using a 3-amino-4-chloro benzohydrazide affinity column. First, codon-optimized HRP A2A gene was amplified and inserted into pPICZαC. So, obtained pPICZαC-HRPA2A was cloned in E. coli cells. Then, P. pastoris X-33 cells were transformed with linearized recombinant DNA and a yeast clone was cultivated for extracellular recombinant HRP A2A (rHRP A2A) enzyme production. Then, the purification of this enzyme was performed in a single step by affinity chromatography. The molecular mass of purified rHRP A2A enzyme was found to be about 40 kDa. According to characterization studies of the purified enzyme, the optimum pH and ionic strength for the rHRP A2A isoenzyme were determined to be 6.0 and 0.04 M, respectively, and o-dianisidine had the highest specificity with the lowest Km and Vmax values. Thus, this is an economical procedure to purify HRP A2A isoenzyme without time-consuming and laborious isolation from an isoenzyme mixture.

A new approach for affinity-based purification of horseradish peroxidase.

We have developed efficient procedure for isolation of horseradish peroxidase (HRP) using aminobenzohydrazide-based affinity chromatography. Sepharose 4B-bounded aminobenzohydrazides are suitable for long-term use and large-scale purification. In this study, 26 aminobenzohydrazide derivatives were synthesized, characterized and defined as new HRP inhibitors. In addition, detailed inhibition effects of these molecules on HRP enzyme were investigated. Affinity matrix was formed by bonding aminobenzohydrazides, which exhibited inhibitory activity to sepharose-4B-l-tyrosine. HRP was isolated from crude homogenate in single step and purification factors were recorded as 1,151-fold (recovery of 8.5%) with 4-amino 3-bromo benzohydrazide and as 166.16-fold (recovery of 16.67 %) with 3-amino 4-chloro benzohydrazide.