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Recent bioinformatic and genetic analyses of several model plant genomes have revealed the existence of a highly abundant group of signaling peptides that are defined as cysteine-rich peptides (CRPs). CRPs are usually in size between 50 and 90 amino acid residues, they are positively charged, and they contain 4-16 cysteine residues that are important for the correct conformational folding. Despite the structural differences among CRP classes, members from each class have striking similarities in their molecular properties and function. The present review presents the recent progress in research on signaling peptides from several families including: EPF/EPFL, SP11/SCR, PrsS, RALF, LURE, and some other peptides belonging to CRP group. There is convincing evidence indicating multiple roles for these CRPs as signaling molecules during the plant life cycle, ranging from stomata development and patterning, self-incompatibility, pollen tube growth and guidance, reproductive processes, and nodule formation.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key redox-sensitive protein, the activity of which is largely affected by oxidative modifications at its highly reactive cysteine residue in the active site of the enzyme (Cys-152). These modifications occur as a result of S-thiolation, S-nitrosylation or disulfide bonds that lead to aggregate formation. The oxidative changes not only affect the glycolytic function but also stimulate the participation of GAPDH in numerous cellular processes. In this review we describe how thiol modification of Cys-152 in GAPDH re-routes metabolic pathways in the cell and converts a metabolic enzyme into a pro-apoptotic factor. Especially interesting issue is the participation of GAPDH in the regulation of expression of endothelin 1 and nitrosylation of nuclear proteins. In the last section we describe involvement of GAPDH in the processes associated with neurodegenerative diseases.

γ-Cystathionase (CTH, EC: 4.4.1.1), an enzyme widely distributed in the world of prokaryotic and eukaryotic organisms, catalyzes the formation and transformations of sulfane sulfur-containing compounds and plays a pivotal role in the L-cysteine desulfuration pathway. Human, tetrameric CTH is composed of two dimers and each monomer binds pyridoxal phosphate (PLP). The gene, located on the short arm of chromosome 1, consists of 13 exons and 12 introns. As a result of alternative splicing, three isoforms of human CTH arise. Analysis of genetic variations of the CTH encoding gene showed a large number of polymorphisms. A decrease of the expression of CTH entails a drop in the level of cysteine , glutathione (GSH), taurine and hydrogen sulfide (H2S) in the cells and, more importantly, leads to cystathioninuria. H2S, endogenously formed by CTH, affects the vasodilation and regulation of blood pressure. CTH knockout mice have decreased levels of H2S, hypertension, and reduced capacity for vascular endothelium relaxation. Overexpression of the gene encoding CTH in the cells leads to increased production of H2S. H2S plays a role in protection of neurons against oxidative stress, and stimulates an increase in γ-glutamylcysteine synthetase and thereby an increase in the level of GSH. Sulfurtransferases, including CTH, can locally prevent oxidative stress due to reversible oxidation of - SH groups in the presence of increased levels of reactive oxygen species, and reduction in the presence of GSH and/or reduced thioredoxin.

Recently published international recommendations including Global INitiative for Asthma, PRACTicing ALLergology and Allergic Rhinitis and its Impact on Asthma offer antileukotriene drugs for adult and childhood asthma and allergic rhinitis. In this article we discuss the arguments for and against antileukotriene drugs therapy in the treatment of obstructive lung diseases and rhinitis.

It is well known for ca. two decades that nitric oxide regulates many life processes both in animals and in plants. The list of processes controlled by NO is steadily expanding, and some of the mechanisms of action of this small molecule are being unravelled and understood. Nitric oxide is exerting its action through addition to the transition metal ions which normally function as protein cofactors; in this way NO regulates, e.g., the activity of cytoplasmic guanyl cyclase. Recently, however, more and more often direct structural modifications of peptidyl amino acid residues are being studied. Particular attention is being paid to the modifications of cysteine (S-nitrosylation) and tyrosine (nitration) residues with respect to their putative signalling functions. It is also known that these modifications are modulating activities of numerous proteins. In this paper we are discussing structural modifications of amino acid residues by NO taking into account the conditions which should be fulfilled to consider their signalling functions. Moreover, we also present available methodologies for their analysis and identifications of modified proteins.

Glutathione plays a key role in maintaining a physiological balance between prooxidants and antioxidants, crucial for the life and death of a cell. Glutathione occurs in the human body in several redox forms, of which reduced glutathione (GSH), oxidized glutathione (GSSG), S-nitrosoglutathione (GSNO), and mixed disulfides of glutathione with proteins are the most important. There is a clear relationship between the levels of different redox forms of glutathione and the regulation of cellular metabolism in a broad sense. Therefore, each of these forms of glutathione can be beneficial or harmful to the organism depending on the cell type and its metabolic status. In such a situation, elevation of GSH level can constitute a very important factor aiding treatment. A rise in GSH level is beneficial in all pathological states, accompanied by lowered GSH content, while a lowering of GSH level is an indication to induce short-term immunosuppression required in organ transplantation and in tumor cells to selectively increase their sensitivity to chemo- and radiotherapy. GSH itself cannot be used as a therapeutic since it is not transported through plasma membranes. Cysteine, an amino acid which limits glutathione biosynthesis, also cannot be used in therapy due to its high neurotoxicity. For this reason, there is currently an intensive search for possibilities of modulating cellular glutathione and cysteine levels, and this problem can be the subject of interdisciplinary studies combining such scientific fields as biology, pharmacology, toxicology, and clinical medicine.

The majority of epitopes for TSH receptor (TSHR) stimulating autoantibodies are clustered around the Nterminal region of the TSH receptor. The characteristic feature of this region is the presence of four cysteine residues. It was proposed that cysteines in positions 29 and 41 in the receptor are connected by disulfide bonds and they are the target for receptor stimulating antibodies. The present study was aimed to check this possibility. The synthetic peptides: peptide corresponding to the part of TSHR containing the above 29-41 cysteine bond, the peptide similar to this peptide but without disulfide bond and the control peptide, containing sequence absent in the receptor were used for rabbit immunization. The thyroid status of all immunized rabbits was the same. Rabbits immunized with peptides related to TSHR generated antisera reactive with TSHR in immunoenzymatic assay. To check specificity of this reaction the influence of the peptides and the antisera on TSH binding to the receptor in competitive assay (TRAK) and their influence on adenylate cyclase activity were studied. It was found that neither synthetic peptides nor antiserum from any rabbit influenced TSH binding to the receptor in TRAK. In contrast low, but significant adenylate cyclase stimulating activity was noticed for antisera from two of six rabbit immunized by peptide containing the disulfide bond. We concluded that such a bond between cysteine residues 29 and 41 are present in TSHR in the site of stimulating antibodies epitope.

Glutathione (GSH) is in a constant state of metabolic turnover. Because it is actively synthesized, it also must be degraded. In the first step of GSH synthesis, an amide linkage is formed between cysteine and glutamate catalyzed by gamma-glutamylcysteine synthetase. GSH synthetase catalyzes the reaction between amine residue of glycine and the cysteine carboxyl from gamma-glutamylcysteine dipeptide to form GSH. GSH is transported out of the cell and degraded by the membrane-bound enzyme gammaGT, which removes the gamma-glutamyl moiety, and by dipeptidases, which remove the glycine moiety. Glutathione is present in most of the plants and animals' tissues that constitute human diet. Thiol redox cycles play central roles in the antioxidant defense network. Lipoate and vitamins and other reducing factors affect the increase in glutathione concentrations in cells by the rise of the concentrations of reduced cysteine. The level of GSH in humans may be increased by taking different glutathione monoester (drug) or factors reducing cystyne to cysteine and increasing availability of this amino acid to GSH synthesis. GSH plays a critical role in cellular mechanisms that lead to cell death. The cancer cells resistant to apoptosis have higher intracellular GSH levels. The fact that numerous diseases are induced by RFT (that cause glutathione depletion) it seems that an in-depth study of the dietetic and pharmacological manners of manipulation of the GSH amount and availability may become in future a tool of great importance in the prevention of many illnesses.

It has been commonly accepted that oxidative stress is involved in pathogenesis of many serious and even lethal health disturbances, including neurodegenerative diseases, diabetes, alcoholic disease, viral and bacterial infections. In this paper we discuss the protective antioxidative role of glutathione, the predominant non-protein thiol in mammalian cells. We also emphasize the perspectives of glutathione therapy i.e. application of both cysteine and glutathione precursors.

Correct diagnosis in patients with side effect during benzylpenicillin (penicillin G) treatment is highly problematic. It is accepted, that hypersensitivity to penicillin is overdiagnosed. Very little qualitative information is available on the diagnostic and differentiation of penicillin allergy. On present stage it is not techniques permitting to exclude anaphylaxis. This paper describe topical knowledge about risks administration of benzylpenicillin to patients suspected of penicillin hypersensitivity. Precious advice in diagnostic procedures and therapeutic management was given.

The sterilization effect was analysed on the nutritional value of two protein types (milk/casein) and fish (cod). By chemical-biological method (determination of digestibility, assimilate-ability and growth yield) the level of accessible methionine and cysteine, and taurine level as a metabolite of sulphur-containing amino acids were determined in the liver and urine of experimental animals. Cod protein and casein subjected to technological processing showed lower digestibility, assimilate-ability and growth yield as compared with raw protein. The serum level of biologically active sulphur-containing amino acids methionine and cysteine was lower also. A significant correlation was found between the results of the biological assessment of the nutritional value of protein, and the levels of methionine and cysteine in diet on the one hand, and the content of taurine in the liver and urine of rats, on the other hand. The possibility of assessment of the nutritional value of protein based on urinary taurine level is a simple and non-invasive method based on the metabolism of sulphur-containing amino acids in the organism of humans and animals which encourages for further studies.