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Bioactive peptides from meat industry by-products as potential antimicrobial agents based on BIOPEP-UWM database

Kęska P., Stadnik J., Kononiuk A., Libera J., Wójciak K. M.

Biotechnology and Food Science

2018

Vol. 82, nr 2

75--84

New peptides with potential antimicrobial activity, encrypted in protein sequences of meat industry by-products were searched with bioinformatics tools using BIOPEP-UWM database. The potential of major proteins as a source of biologically active peptides with antibacterial, antiviral and antifungal activity were considered. As a result, collagen, hemoglobin, fibrinogen and selected meat tissue proteins (creatine kinase, myosin, titin) has been shown to contain short motifs responsible for antibacterial properties. The peptides with antiviral and antifungal properties were not detected.

Pochodne fosforylowanych cukrów jako inhibitory syntazy GLcN-6-P

Melcer A.

Wiadomości Chemiczne

2010

[Z] 64, 9-10

771-786

A reaction catalyzed by glucosamine-6-phosphate synthase (L-glutamine: D-fructose-phosphate amidotransferase, Glms) is the first step committed to the amino-sugar biosynthetic pathway of all living organisms [1]. This is in particular the only endogeneous access to hexosamines which are absolutely required in the edification of microbial cell walls. Glucosamine-6-phosphate synthase was proposed as a target for antifungal chemotherapy and a search for its selective inhibitors as potential antifungals has been continued [2]. This enzyme catalyzes two coupled enzymatic reactions. The first is the hydrolysis of glutamine to yield glutamate and nascent ammonia, which is transferred to Fru-6-P. The second reaction is the isomerization of Fru-6-P to an aldose, corresponding to Heyns rearrangement (3, 4). Like other amidotransferases, GlmS is organized into two domains: the NH2-terminal glutamine amidotransferase domain, which catalyzes the hydrolysis of glutamine, and the COOH-terminal synthase domain, which catalyzes the isomerization (5-8). The glutamine hydrolysis reaction has been studied extensively and utilises the NH2-terminal cysteine thiol, which forms a g-glutamyl thioester intermediate during the reaction. This catalytic role was confirmed by conversion of the NH2-terminal cysteine to alanine using site-directed mutagenesis which abolished enzymatic activity [2]. The already known specific inhibitors of GlcN-6-P synthase belong to two different structural groups: L-glutamine mimics and analogues of the putative transition state intermediates. In general, glutamine amidotransferases are inactivated by glutamine afinity analogues such as 6-diazo-5-oxo-L-norleucine and 6-chloro-5-oxo-L-norleucine (chloroketone), which alkylate the essential cysteine residue (5, 6, 9). Indeed, many of the active site-directed irreversible inactivators developed for GlmS contain an electrophilic function at the ă -position of glutamate and react irreversibly with the NH2-terminal cysteine residue. More recently, attempts to develop carbohydrate-based inhibitors have been made with the hope of developing higher specificity (10-13). The second group of compounds comprises derivatives of phosphorylated aminosugars, including: 2-amino-2-deoxy-D-glucitol-6-phosphate (ADGP), arabinose-5-phosphate oxime and 5-methylenephosphono-D-arabinohydroximolactone, as the most powerful GlcN-6-P synthase inhibitors [11-15]. These compounds exhibit a very poor, if any, antifungal activity. This paper describes the inhibition of GlmS by several analogues of the cis-enolamine intermediate in an attempt to probe the structural requirements for potent inhibition of this enzyme. The energetic contribution of the 2-amino group to binding of the product and the cis-enolamine intermediate is determined.