V. I. Novoselov

Identification of a 28 kDa secretory protein from rat olfactory epithelium as a thiol-specific antioxidant

The 28 kDa secretory protein is one of the abundant water-soluble proteins in olfactory epithelium of mammals. Analysis of partial amino acid sequence of the 28 kDa protein strongly suggested that it belongs to a new family of highly conserved antioxidant proteins requiring thiol for their antioxidant activity (TSA/AhpC family). In the present study, we found the 28 kDa protein to have thiol-dependent antioxidant activity, thereby protecting radical-sensitive proteins such as glutamine synthetase and hemoglobin from oxidative modification caused by thiol-dependent metal ion-catalyzed oxidation system. The purified 28 kDa protein did not possess catalase or glutathione peroxidase activities, and required thiols to exhibit its antioxidant activity. The 28 kDa protein is the first member of the family of thiol-specific antioxidants identified in olfactory epithelium and the first secretory protein shown to be thiol-specific antioxidant.

Localization of 28-kDa peroxiredoxin in rat epithelial tissues and its antioxidant properties

Abstract. Peroxiredoxins are a novel family of antioxidant proteins that specifically prevent enzymes from metal-catalyzed oxidation. The localization of a member of the mono-cystein subfamily of peroxiredoxins, the 28-kDa protein, in different rat tissues and its antioxidant properties were investigated. By immunoblotting, the 28-kDa peroxiredoxin was found to be most highly concentrated in olfactory epithelium and present in all tissues tested (skin, lung, trachea, kidney, womb, and brain). Immunostaining with rabbit polyclonal antibody raised against the 28-kDa peroxiredoxin revealed the particularly high level of the 28-kDa peroxiredoxin immunoreactivity in air-contacting areas (apical regions and mucus of the olfactory and respiratory epithelium and skin epidermis), which are continually exposed to numerous air-borne reactive oxygen species. In the apical regions of the olfactory and respiratory epithelium, the 28-kDa-peroxiredoxin immunogold labeling outlined microvilli and cilia and was mainly located in sustentacular cells and in respiratory and goblet cells, as electron-microscopic analysis revealed. In skin epidermis, the 28-kDa peroxiredoxin immunoreactivity was confined to the granular layer and specifically concentrated in sebaceous glands of hair follicle. In situ hybridization with 33P-labeled antisense RNA probe revealed the expression of the 28-kDa peroxiredoxin mRNA in tissues with a high level of the 28-kDa peroxiredoxin immunoreactivity. Immunodepletion of the 28-kDa peroxiredoxin profoundly decreased the antioxidant activity of the olfactory tissue extract.

A novel 45 kDa secretory protein from rat olfactory epithelium: primary structure and localisation

cDNA clones encoding the 45 kDa protein were isolated from a rat olfactory epithelium cDNA library and their inserts were sequenced. The reconstructed protein sequence comprises 400 amino acids with a calculated molecular mass of 46 026 Da. A homology was revealed between the amino acid sequence of the 45 kDa protein and the proteins involved in the transfer of hydrophobic ligands. Using in situ hybridisation, the 45 kDa protein mRNA expression was detected in the layer of supportive cells of olfactory epithelium, apical region of trachea, surface layer of the ciliated bronchial epithelium in lung and in skin epidermis.

Novel 28-kDa secretory protein from rat olfactory epithelium

We have isolated a novel secretory 28‐kDa protein which is an abundant component of the rat olfactory mucosa. The partial sequence of the 28‐kDa protein has been determined. The amino acid sequence of the 28‐kDa protein is similar to that of non‐selenium glutathione peroxidase from bovine ciliary body. The 28‐kDa protein catalyzed decomposition of the hydrogen peroxide as well as organic hydroperoxides by reduced glutathion and seems to be a member of the glutathion peroxidases family.

Water-soluble GTP-binding protein from rat olfactory epithelium

Rat olfactory epithelium and ciliar cytosol of olfactory cells contained the water‐soluble 45 kDa protein which was revealed by antibodies against a peptide fragment of the α‐subunits common to the G‐proteins. No analogous proteins were found in other rat tissues. According to the photo‐affinity labeling, the 45 kDa protein possessed a high affinity to GTP; it also exhibited a low GTP hydrolytic activity.

Peroxiredoxins, a new family of antioxidant proteins

Current ideas are discussed about the structures and mechanisms of action of proteins that have been united at present into a family of thiol-specific antioxidants or peroxiredoxins, which protect the cells of different organisms from the action of hydrogen peroxide. Peroxiredoxins fulfill the same function as antioxidant enzymes such as catalases and glutathione-dependent peroxidases; however, their catalytic activity is lower than that of these enzymes. The level of expression of genes of peroxiredoxins is increased in many pathological states accompanied by oxidative stress, and today there is direct evidence for the important role of peroxiredoxins in the vital activity of cells.

Peroxiredoxins as multifunctional enzymes

Peroxiredoxins are an evolutionary ancient widespread group of selenium-independent peroxidases. Peroxiredoxins protect cells from various peroxides, play an important role in maintaining redox homeostasis, and are additionally involved in transmitting extracellular and intracellular signals. The review considers peroxiredoxins from different kingdoms of living organisms and discusses the recent data on their structure, function, and the expression regulation of their genes.

The effect of negative air ions on the respiratory organs and blood

The effect of ionized air containing negatively charged ions at a concentration of 320000–350000 ions/cm3 inhaled by rats was studied. It was demonstrated that the inhalation of negative air ions for 60 min activated the secretion of goblet cells without impairing the tracheal mucosa and changing the protein profile of bronchoalveolar lavage. It was also found that the level of spontaneous production of reactive oxygen species by unfractionated blood cells increased after the action of negative air ions in both males and females. However, the intensity of their generation induced by opsonized zymosan increased only in females. Different sensitivities of the female and male blood antioxidant enzymes—superoxide dismutase and glutathione reductase—to negative air ions were observed. These results allow the effect of negative air ions on the respiratory organs and blood to be interpreted as priming and weak activation via a direct action on the mucosa of primary target respiratory organs and then on the blood.

The subunits of specific odor-binding glycoproteins from rat olfactory epithelium.

The specific odor‐binding glycoproteins have been isolated from rat olfactory epithelium. They consist of two subunits, gp88 and gp55. Subunit gp88 is capable of odorant binding.

The novel approach to the protein design: active truncated forms of human 1-CYS peroxiredoxin.

Abstract The object of the present study is the verification of a new approach to the design of the active truncated forms of enzymes. The method is based on a new way of investigating the protein sequences—the ANalysis of Informational Structure (ANIS). The analysis of informational structure allows to determine the hierarchically organized structures (IDIC-trees) formed by the sites with the Increased Degree of Informational Coordination between residues. The proposed approach involves the consequent removal of the fragments corresponding to the individual IDIC-trees from the wild-type enzyme sequences. The described procedure was applied to the design of the active truncated form of human 1-CYS peroxiredoxin (PrxVI). Two variants of the PrxVI truncated sequences were proposed according to ANIS method. These truncated forms of the enzyme were expressed in E. coli and purified. The respective antioxidant activities were measured. It was shown that one of the truncated recombinant proteins retains more than 90% of the wild-type PrxVI enzymatic activity. According to the results of our study we can assume that ANIS method can be an effective tool for the design of the active truncated forms of the enzymes or the chimeric proteins which combine the enzymatic activities of their wild-type prototypes.