On the Presence of Gluten-Cleaving Activity in Sodiomyces alkalinus and S. magadiensis Strains.

Special enzymes are necessary for producing gluten-free foods, and specific proteolytic enzymes with gluten-degrading activity may be used as oral treatments for celiac disease. Enzymes of the kind were sought, identified, and preliminarily characterized in two strains of the alkaliphilic microscopic fungi Sodiomyces alkalinus and S. magadiensis. Post-glutamine cleaving activity was for the first time observed in the strains along with proline-cleaving activities of dipeptidyl peptidase 4 (DPP4) and proline aminopeptidase (PAP), allowing efficient hydrolysis of both proline/glutamine-rich gluten peptides and whole gluten. The optimal pH and pH-dependent stability were determined for the peptidases in question. All of the enzymes shown to cleave the prolyne/glutamine-containing bonds were assigned to the serine peptidase group and were found to be stable in moderately acidic and alkaline conditions. Owing to their activities, the peptidases are promising as tools to produce gluten-free foods and to design diets for gluten-intolerant patients.

[Comparative analysis of tobacco and Arabidopsis insertional mutants, transformed with equal vector constructions].

We have analyzed genetic effects of heterologous plant genes insertion on genome functioning of higher plants, belonging to different systematic groups (tobacco, Arabidopsis). Plants of different species were responding differently to the insertion of the same transgene, which is likely to be associated with the location of alien DNA insertion and could manifest in morphological changes spectrum and target gene expression level.

[Properties of post-proline cleaving enzymes from Tenebrio molitor].

Two post-proline cleaving enzymes PRE1 and PRE2 with molecular masses of 101 and 62 kDa, respectively, capable of hydrolyzing Z-AlaAlaPro-pNA were isolated for the first time from the midgut of the flour beetle Tenebrio molitor and characterized. PRE1 is active only in acidic media, with a maximum at pH 5.6, whereas PRE2, both in acidic and alkaline media with a maximum at pH 7.9. Using inhibitory analysis, both PRE1 and PRE2 were shown to belong to serine peptidases. Some data indicate that a Cys residue is located close to the PRE2 active site. Z-Pro-prolinal, a specific inhibitor of prolyl oligopeptidases, inhibits completely PRE2 and partially PRE1. The substrate specificities of the isolated enzymes were studied. It was shown that Z-AlaAla-Pro-pNA was the best substrate for PRE1, and Z-AlaPro-pNA, for PRE2. The combination of the studied properties allowed characterization of PRE2 as a prolyl oligopeptidase.

[Extracellular proteases of mycelial fungi as participants of pathogenic processes].

The interest in proteases secreted by mycelial fungi is due to several reasons of which one of the most important is their involvement in the initiation and development of the pathogenic process. A comparison of saprophytic and phytopathogenic mycelial fungi revealed one characteristic feature, namely, the appearance of a new trypsin-like activity in phytopathogens that is absent in saprophytes. To clear up the question of whether the degree of pathogenicity of a fungus is related to the activity of secreted trypsin-like protease, several species of Fusarium of various pathogenicity were compared. In two species, F. sporotrichioides (which causes ear fusa-riosis of rye) and F. heterosporum (the causative agent of root rot in wheat), a clear correlation between the activity and pathogenicity was revealed: the more pathogenetic F. sporotrichioides exhibited a higher extracellular trypsin-like activity than the less pathogenetic species F. heterosporum. Thus, the presence of trypsin-like activity in a saprotroph-pathogen pair may be an indicator of the pathogenicity of a fungus; in some cases, the value of this activity may indicate the degree of its pathogenicity. This suggests that trypsin-like proteases specific to phytopathogens are directly involved in the pathogenetic process, probably, through interaction with the "sentry" protein or the product of the resistance gene.

[Proteolytic enzymes of the fungi: extracellular proteases of xylotrophic basidiomycetes].

Proteolytic enzymes of the fungi attract attention of investigators due to many reasons among which their large diversity, wide substrate specificity, stability under extreme conditions (pH, temperature) are most important. Their functional significance, including various processes, from hydrolysis of macromolecular substrates under deficiency of nitrogen compounds to initiation and maintenance of pathogenesis, is also very interesting. The present review deals with classification and biochemical properies of extracellular fungal proteinases, their physiological role as well as fields of practical application. Much attention is given to pecularities of extracellular proteinases of xylotrophic basidiomycetes-- an exceedingly important group of the fungi from the point of functioning of biological communities, and their participation in biodestruction of plant waste which are also used as source of food and medicinal preparations. Special attention is focused on regulation of synthesis and secretion of extracellular proteinases of xylotrophic basidiomycetes.

[Degradation of proteinaceous substrates by xylotrophic basidiomycetes].

The ability of various xylotrophs to produce extracellular proteolytic enzymes has been studied, with emphasis on medium-related factors regulating their secretion. Direct measurement of proteolytic activity in the culture liquid and postelectrophoresis determination of protease activity in polyacrylamide gel copolymerized with gelatin demonstrated that the secreted enzymes are quantitatively and qualitatively diverse. Activity levels of extracellular proteolytic enzymes strongly depend on pH and contents of protein and carbohydrate in the medium. All secreted proteases notably differed in molecular weight (of 51 kDa or higher and in excess of 95 kDa) and belonged mostly to two classes of proteolytic enzymes (serine proteases and metalloproteinases).

[Extracellular proteinases of filamentous fungi as potential markers of phytopathogenesis].

The presence of proteins in the culture liquid of filamentous fungi under study was found to induce the secretion of proteinases. The inhibitory analysis of the major extracellular proteinases of the saprotrophic fungus Trichoderma harzianum and the phytopathogenic fungus Alternaria alternata showed that they both belong to the group of serine proteinases. The substrate specificity of these proteinases and their sensitivity to inhibitors suggest that the enzyme of T. harzianum is a subtilisin-like proteinase and the enzyme of A. alternata is a trypsin-like proteinase. This difference between the proteinases may reflect the physiological difference between their producers (saprotroph and phytopathogen).

[Proteinase inhibitors as antistress proteins in higher plants].

Physicochemical and functional characteristics of plant protein proteinase inhibitors as antistress biopolymers were studied to determine the mechanisms for plant resistance to phytopathogens and to obtain disease-resistant cereal and leguminous cultures. The activity of trypsin, chymotrypsin, and subtilisin inhibitors varied in monocotyledonous and dicotyledonous cultures. Study varieties of leguminous and cereal cultures were shown to contain endogenous inhibitors specific to proteinases of phytopathogenic fungi Fusarium, Colletotrichum, Helminthosporium, and Botrytis. These inhibitors were characterized by species specificity and variety specificity. Protease inhibitors from buckwheat seeds inhibited proteases of fungal pathogens and suppressed germination of spores and growth of the fungal mycelium. Our results suggest that proteinaceous inhibitors of proteinases are involved in the protective reaction of plants under stress conditions.

[Protease inhibitors: use to increase plant tolerance to insects and pathogens].

The review deals with analysis of the possibility of the use of genes of inhibitors of proteolytic enzymes of plants to increase plant tolerance to insect pests and phytopathogens. The idea of using protease inhibitors for plant defense is strongly supported, first, by their wide distribution in plant tissues and high activity towards various proteolytic enzymes of insects, bacteria and fungi. The results obtained for the last years indicate that the genetic engineering approach is perspective for solving of this kind of problems. The main losses and advantages of the discussed approach are also considered. The described approach for increase of plant tolerance to insects and pathogens has few advantages as compared to traditional ones and belongs to ecologically pure technologies.

[Effect of the antioxidant ionol on proteolytic apparatus of aging coleoptiles of wheat seedlings grown in light]. / Vliianie antioksidanta ionola na proteolitcheskii apparat stareiushchikh koleoptilei vyrashchivaemykh na svetu prorostkov pshenitsy.

The dynamics of changes in total proteolytic activity and activities of various groups of proteases in the coleoptiles of 3- to 12-day-old wheat seedlings grown in light with and without antioxidant BHT (2,6-di-tert-butyl-4-methylphenol) was studied. It was established that the specialized proteases that easily hydrolyze specific synthetic substrates and the enzymes actively hydrolyzing histone H1 dominate in young coleoptiles of 3- to 4-day-old seedlings. Proteases that degrade equally well the majority of the studied substrates are accumulated in the cells of old coleoptiles of 11- to 12-day-old seedlings. Under the effect of BHT, the plants grown in light (in comparison with etiolated seedlings) demonstrated a somewhat changed dynamics of proteolytic activity in young coleoptiles and the disappearance of proteases active toward histone H1. An inhibitory analysis revealed a relative domination of cysteine proteases in young coleoptiles at the initial development stage of seedlings, whereas the fraction of serine proteases markedly increased in old coleoptiles. We presume that the revealed quantitative and qualitative changes in the proteolytic apparatus of the coleoptile cells induced by BHT may be largely responsible for the retardant and geroprotective effect of this antioxidant in plants.

[Amino acid sequence of anionic protease inhibitors from buckwheat seeds]. / Aminokislotnye posledovatel'nosti anionnykh ingibitorov proteaz iz semian grechikhi.

Complete amino acid sequence of IT1 protease inhibitor and partial amino acid sequences of IT2 and IT4 protease inhibitors from buckwheat Fagopyrum esculentum Moench seeds were determined by automatic Edman degradation and mass spectrometry. IT1 inhibitor comprises 69 amino acid residues and its molecular mass is 7743.8 D. N-terminal 48 amino acid residues of IT2 inhibitor are identical to similar sequence of IT1 inhibitor. The sequence of 10 amino acid residues of IT4 inhibitor is completely identical to a part of the sequence of IT1 inhibitor C-terminally adjacent to its active site. Analysis of amino acid sequences of IT1, IT2 and IT4 inhibitors suggests that the proteins are the members of the potato proteinase inhibitor 1 family and include Arg-Asp residues in their active site.

[Inhibition of exogenous serine proteinases by a trypsin inhibitor from the buckwheat IT-1 seeds]. / Ingibirovanie ékzogennykh serinovykh proteinaz ingibitorom tripsina iz semian grechikhi IT-1.

The possibility of inhibition of exogenous trypsin- and chymotrypsin-like proteinases by a proteinase inhibitor from buckwheat (IT-1) seeds has been studied. The inhibition constants for bovine trypsin and alpha-chymotrypsin and human granulocyte cathepsin G by IT-1 are equal to 1.1, 67 and 200 nm, respectively. The specificity of IT-1 with regard to its primary sequence adjacent to the active center and to its homology with inhibitors pertaining to the potato inhibitor I family has been carried out. It is concluded that by virtue of the basic nature of the P1 (Arg) residue in the active center IT-1 is not capable to bind human granulocyte elastase.

[Trypsin inhibitor from buckwheat seeds]. / Ingibitor tripsina iz semian grechikhi.

It has been demonstrated that buckwheat seeds contain a proteinaceous inhibitor of trypsin and chymotrypsin. The isolation technique consisted in extraction of the seed flour with water, ammonium sulfate fractionation, isoelectric precipitation, gel filtration on Sephadex G-75 and ion-exchange chromatography on DEAE-Sephadex. The isolated inhibitor is homogeneous according to acidic and basic polyacrylamide gel electrophoresis data. The molecular weight of the inhibitors is about 10 000 as determined by gel filtration on Sephadex G-50; the isoelectric point pI is 5,8; the sedimentation coefficient is 1S. The inhibitor effectively inhibits trypsin, much worse--chymotrypsin and has no effect at buckwheat seed protease, hydrolyzing N alpha-benzoyl-D,L-arginine-p-nitranilide (BAPAase).

[Changes in activity of proteolytic enzymes (BAPAases) in germinating buckwheat and rye seeds]. / O prirode izmenenii aktivnostei proteoliticheskikh fermentov (BAPAaz) v prorastaiushchikh semenakh grechikhi i rzhi.

The interrelationship between the activity of proteolytic enzymes (BAPAases) from buckwheat and rye seeds hydrolyzing Nalpha-benzoyl-DL-arginine-p-nitroanilide (BAPA) and the amount of the antiserum to these enzymes necessary to obtain a certain inhibition level has been studied at different stages of seed germination. The data obtained show that the increase of the BAPAase activity in germinating rye seeds is due to de novo synthesis of this enzyme. During this process antigenically identical enzyme molecules are synthesized in roots and shoots of the developing plant.

[Immunochemical characterization of proteolytic enzymes (BAPAase) from buckwheat and rye seeds]. / Immunokhimicheskaia kharakteristika proteoliticheskikh fermentov (bapaaz) iz semian grechikhi i rzhi.

A comparative study of the immunochemical properties of two serine proteolytic enzymes (BAPases) from buckwheat and rye seeds hydrolyzing N alpha-benzoyl-DL-arginine-p-nitroanilide (BAPA) has been performed. It has been shown that buckwheat and rye seed BAPAases were partially antigenically identical. This was demonstrated using double immunodiffusion in agar and inhibition of one enzyme with an antiserum to the other. At the same time neither of the antisera inhibited trypsin. Thus, buckwheat and rye seed BAPAases have common antigenic determinants and, consequently, common structural features. On the other hand, these enzymes probably have no common structural elements with trypsin.

[Benzoyl-DL-arginine-p-nitroanilidase from buckwheat seeds. Properties and substrate specificity]. / N, al'fa-benzoil-D,L-arginin-n-nitroanilidaza iz semian grachikhi. Svoistva i substratnaia spetsifichnost'

A proteolytic enzyme, hydrolyzing N-benzoyl-D,L-arginine-p-nitro-anilide (BAPAase), has been isolated from the buckwheat seeds (Fagopyrum esculentum). The enzyme was purified 400-fold and was homogeneous according to isoelectrofocusing and disc electrophoresis in polyacrylamide gel. The molecular weight of the BAPAase was determined to be 65000 by gel-chromatography and 70000 by polyacrylamide gel electrophoresis. The sedimentation coefficient of the BAPAase was found to be 4.3 S, the isoelectric point--pH 4.5. The enzyme split peptide, esteric and amide bonds formed by carboxyl groups of lysine and arginine in synthetic substrates. The enzyme did not hydrolyse fibrinogen, did not activate chimotrypsinogen, weakly hydrolyzed histones and casein and strongly--protamine. The BAPAase did not hydrolyse albumins and globulins from the buckwheat seeds, and weakly hydrolyzed glutelins. The study of the products of the hydrolysis of salmine and sturine by BAPAase showed that the enzyme split internal peptide bonds in these substrates, and, thus, it is an endopeptidase.

[Phenolic inhibitor of a proteinase from buckwheat seeds]. / Ingibitor fenol'noi prirody proteinazy iz semian grechikhi

An inhibitor of a proteolytic enzyme (BAPAse), hydrolyzing N, alpha-benzoyl-DL-arginine-p-nitroanilide (BAPA), has been found in the buckwheat seeds. The inhibitor is located in the seed coat. The inhibitor is shown to have a phenolic nature and, probably, is a proantocyanidine.

[Properties and substrate specificity of proteinase from buckwheat seeds]. / Svoistva i substratnaia spetsifichnost' proteinazy iz semian grechikhi

A thiol proteinase was isolated from buckwheat seeds and purified 300-fold, using ammonium sulfate, acetone fractionation ion-exchange chromatography on Sephadex CM-50 and electrofocussing. The proteinase preparation obtained was found homogenous after polyacrylamide gel electrophoresis at pH 4.5. The molecular weight of the enzyme (75.000) was determined by gel-filtration through Sephadex G-100. The activation of proteinase by cysteine, 2-mercaptoethanol and dithiothreitol, its inhibition by p-chloromercurybenzoate and the absence of inhibition by diisopropyl fluorophosphate and EDTA suggest that the enzyme isolated is a thiol proteinase. The enzyme hydrolyzed many peptide bonds in the B-chain of insulin, showing high substrate specificity. The glutelin and globulin fractions of buckwheat seed proteins were hydrolyzed by the enzyme. It is assumed that the hydrolysis of reserve proteins of buckwheat seeds is the main function of the proteinase isolated.