scholarly journals The role of cysteine in the formation of domain structures of papain and legumin in peas, involved in limited proteolysis

2022 ◽  
Vol 11 (4) ◽  
pp. 642-650
Author(s):  
Yu. I. Matveev ◽  
E. V. Averyanova
Keyword(s):  
Seed Germination ◽  
Hydrogen Bonds ◽  
Proteolytic Enzymes ◽  
Limited Proteolysis ◽  
Seed Proteins ◽  
Preliminary Heat Treatment ◽  
Amino Acid Residues ◽  
Protein Secondary Structures ◽  
Domain Structures ◽  
Stable Domains

The limited use of plant proteins for food is explained by their low bioavailability and poor digestibility by enzymes of the gastrointestinal tract. Partially reproduced enzymatic processes of limited proteolysis that occur during seed germination are used to modify and improve the edibility characteristics of seed proteins. The present work discusses the possibility of reducing the duration of seed germination processes by optimising the conditions and parameters of limited proteolysis. To optimise manufacturing high-quality final product, enzymes (additional to the natural enzymes in the seed) and proteolysis conditions (in this case, temperature), as well as added substances (hydrolysis activators), were selected. The influence of cysteine on the formation of domain structures of proteins (enzymes and globulins) was evaluated. The proposed expressions can be used to determine those fragments of protein molecules that form stable domains and become unstructured when exposed to enzymes. Optimal conditions for limited proteolysis were identified based on the physical mechanism of action of papain-like proteolytic enzymes on pea legumin LegA (3KSC, CAA10722). It is shown that the decomposition of protein secondary structures takes 6–8 times longer, since the formed hydrogen bonds limit the access of enzymes to the corresponding amino-acid residues. It is also demonstrated that the decomposition of hydrogen bonds, e.g. by preliminary heat treatment of proteins, will broaden the prospects for limited proteolysis.

Damage of Amino Acid Residues of Proteins after Reaction with Oxidizing Lipids: Estimation by Proteolytic Enzymes

1984 ◽  
Vol 49 (4) ◽  
pp. 1082-1084 ◽  
Author(s):  
TERUYOSHI MATOBA ◽  
DAIZO YONEZAWA ◽  
BABOO M. NAIR ◽  
MAKOTO KITO
Keyword(s):  
Amino Acid ◽  
Proteolytic Enzymes ◽  
Amino Acid Residues

Recruited lysosomal enzymes as major digestive enzymes in insects

2019 ◽  
Vol 47 (2) ◽  
pp. 615-623 ◽  
Author(s):  
Walter R. Terra ◽  
Renata O. Dias ◽  
Clélia Ferreira
Keyword(s):  
Digestive Enzymes ◽  
Lysosomal Enzymes ◽  
Proteolytic Enzymes ◽  
Seed Proteins ◽  
Amino Acid Sequences ◽  
Kinetic Properties ◽  
Selective Pressures ◽  
Mass Recruitment ◽  
Critical Regions ◽  
Protein Diets

Abstract The mass recruitment to the midgut contents of lysosomal proteolytic enzymes occurred in insects under three major selective pressures. Hemipteran (true bugs, aphids, and cicadas) ancestors lost their serine peptidases (SP) on adapting to feed on protein-free plant sap. When they returned to protein diets, their cathepsins L and B were recruited to replace their lost SP. Among beetles of the series Cucujiformia, cathepsins L were recruited to hydrolyze ingested plant inhibitors that affect their major SP and/or to deal with special seed proteins, such as prolamins. Larval flies have a very acid middle midgut and use cathepsin D to digest bacteria from their infected food. All the recruited enzymes originated from duplicated genes. The recruited digestive enzymes differ from their lysosomal counterparts in critical regions of their amino acid sequences that resulted in changes in substrate specificities and other kinetic properties. The discharge of digestive cathepsins in the midgut contents, instead of lysosomes, seems to be a consequence of their overexpression or the existence of new targeting signals. Their activation at the midgut contents occurs by an autoactivation mechanism or with the help of other enzymes or by a combination of both. The targeting to lysosomes of the insect lysosomal enzymes does not follow the mammalian mannose 6-phosphate route, but an incompletely known mechanism.

scholarly journals Proteolytic interconversion and N-terminal sequences of the Citrobacter diversus major β-lactamases

1991 ◽  
Vol 275 (3) ◽  
pp. 629-633 ◽  
Author(s):  
N Franceschini ◽  
G Amicosante ◽  
M Perilli ◽  
M Maccarrone ◽  
A Oratore ◽  
...  
Keyword(s):  
Klebsiella Oxytoca ◽  
Limited Proteolysis ◽  
Major Product ◽  
Beta Lactamase ◽  
Amino Acid Residues ◽  
Beta Lactamases ◽  
Citrobacter Diversus ◽  
High Degree ◽  
Papain Digestion ◽  
Degree Of Similarity

The N-terminal sequences of the two major beta-lactamases produced by Citrobacter diversus differed only by the absence of the first residue in form II and the loss of five amino acid residues at the C-terminal end. Limited proteolysis of the homogeneous form I protein yielded a variety of enzymatically active products. In the major product obtained after the action of papain, the first three N-terminal residues of form I had been cleaved, whereas at the C-terminal end the treated enzyme lacked five residues. However, this cannot explain the different behaviours of form I, form II and papain digestion product upon chromatofocusing. Form I, which was sequenced up to position 56, exhibited a very high degree of similarity with a Klebsiella oxytoca beta-lactamase. The determined sequence, which contained the active serine residue, demonstrated that the chromosome-encoded beta-lactamase of Citrobacter diversus belong to class A.

scholarly journals The cyclol hypothesis and the “globular” proteins

1937 ◽  
Vol 161 (907) ◽  
pp. 505-524 ◽  
Keyword(s):  
Amino Acid ◽  
Hydrogen Bonds ◽  
Ad Hoc ◽  
Globular Proteins ◽  
The Body ◽  
Amino Acid Residues ◽  
Native Protein ◽  
Orderly Arrangement

A number of facts relating to proteins suggest that the polypeptides in native protein are in a folded state (Astbury 1933, 1934; Astbury and Street 1930, 1931; Pryde 1931; Wrinch 1936 a , b , c , 1937 a ; Langmuir, Schaefer and Wrinch 1937). The type of folding must be such as to imply the possibility of the regular and orderly arrangement of hundreds 01 amino-acid residues which to some extent at least is independent of the particular residues in question. We propose therefore to formulate all types of folding which are geometrically possible. Each hypothesis in turn can then be tested in two ways. We may consider its plausibility in itself: and having developed its implications to the farthest possible point, we may test it against known facts by ad hoc experiments. At present two types of folding have been suggested—by means of cyclol links (Wrinch 1936 a , b , c , 1937 a ; Langmuir, Schaefer and Wrinch 1937; Astbury 1936 a , b , c ; Frank, 1936) and by means of hydrogen bonds (Jordan Lloyd 1932; Jordan Lloyd and Marriott 1933; Mirsky and Pauling 1936; Wrinch and Jordan Lloyd 1936). The search for other types of folding is being continued. So far it has not proved possible to discard either theory on the grounds that the type of link postulated is out of the question. It is there­ fore very desirable to test these theories by means of their implications. Accordingly, on this occasion we consider (Wrinch 1937 b , c ) whether the cyclol theory can stand the test of the body of facts relating to the “globular” proteins, established by Svedberg and his collaborators (Svedberg and others 1929, 1930 a , b , 1934 a , b , 1935).

scholarly journals Long-chain polyphosphates impair SARS-CoV-2 infection and replication

2021 ◽  
Vol 14 (690) ◽  
pp. eabe5040
Author(s):  
Veronica Ferrucci ◽  
Dae-Young Kong ◽  
Fatemeh Asadzadeh ◽  
Laura Marrone ◽  
Angelo Boccia ◽  
...  
Keyword(s):  
Amino Acid ◽  
Limited Proteolysis ◽  
High Energy ◽  
Site Directed Mutagenesis ◽  
Linear Polymers ◽  
Amino Acid Residues ◽  
Human Nasal Epithelial Cells ◽  
Antiviral Activities ◽  
Long Chain

Inorganic polyphosphates (polyPs) are linear polymers composed of repeated phosphate (PO43−) units linked together by multiple high-energy phosphoanhydride bonds. In addition to being a source of energy, polyPs have cytoprotective and antiviral activities. Here, we investigated the antiviral activities of long-chain polyPs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In molecular docking analyses, polyPs interacted with several conserved amino acid residues in angiotensin-converting enzyme 2 (ACE2), the host receptor that facilitates virus entry, and in viral RNA-dependent RNA polymerase (RdRp). ELISA and limited proteolysis assays using nano– LC-MS/MS mapped polyP120 binding to ACE2, and site-directed mutagenesis confirmed interactions between ACE2 and SARS-CoV-2 RdRp and identified the specific amino acid residues involved. PolyP120 enhanced the proteasomal degradation of both ACE2 and RdRp, thus impairing replication of the British B.1.1.7 SARS-CoV-2 variant. We thus tested polyPs for functional interactions with the virus in SARS-CoV-2–infected Vero E6 and Caco2 cells and in primary human nasal epithelial cells. Delivery of a nebulized form of polyP120 reduced the amounts of viral positive-sense genomic and subgenomic RNAs, of RNA transcripts encoding proinflammatory cytokines, and of viral structural proteins, thereby presenting SARS-CoV-2 infection in cells in vitro.

Features of the extraction of D‑enantiomers of amino acids from the meat matrix for subsequent analysis using HPLC–MS/MS

Vsyo o myase ◽  
2020 ◽  
pp. 50-52
Author(s):  
Knyazeva A.S. ◽  
◽  
Vostrikova N.L. ◽  
Kulikovskii A.V. ◽  
Utyanov D.A. ◽  
...  
Keyword(s):  
Amino Acids ◽  
Matrix Effects ◽  
Solid Phase ◽  
Proteolytic Enzymes ◽  
Meat Products ◽  
Quantitative Detection ◽  
Array Detector ◽  
Amino Acid Residues ◽  
Post Translational Modifications ◽  
Degree Of Extraction

The article is devoted to the study of the processes of epimerization of L-amino acid residues with the formation of D-enantiomers, which affect the onco-associated properties of food products. A method for the chromatographic separation of optically active D- and L-amino acids using a chiral column has been developed. Measurements of the quantitative content of analytes were carried out using a diode array detector, followed by mass spectrometric confirmation. Methodological approaches to sample preparation are presented. It was revealed that during acid hydrolysis, leucine racemization from D-form to L-form. A procedure has been developed for enzymatic hydrolysis of samples by a complex of proteolytic enzymes, followed by purification of the hydrolyzate by solid-phase extraction. The degree of extraction, matrix effects, and the quantitative detection limit of the technique were determined. The data on post-translational modifications in the structure of proteins and peptides under the influence of technological operations and enzymatic processes in the production of meat products are presented.

scholarly journals The Pivotal Roles of the Epithelial Membrane Protein Family in Cancer Invasiveness and Metastasis

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1620 ◽  
Author(s):  
Ahmat Amin ◽  
Shimizu ◽  
Ogita
Keyword(s):  
Cell Migration ◽  
Cancer Progression ◽  
Cancer Biology ◽  
Transmembrane Domain ◽  
Small Gtpase ◽  
Migration And Invasion ◽  
Amino Acid Residues ◽  
Peripheral Myelin Protein 22 ◽  
Domain Structures ◽  
Cancer Invasiveness

The members of the family of epithelial membrane proteins (EMPs), EMP1, EMP2, and EMP3, possess four putative transmembrane domain structures and are composed of approximately 160 amino acid residues. EMPs are encoded by the growth arrest-specific 3 (GAS3)/peripheral myelin protein 22 kDa (PMP22) gene family. The GAS3/PMP22 family members play roles in cell migration, growth, and differentiation. Evidence indicates an association of these molecules with cancer progression and metastasis. Each EMP has pro- and anti-metastatic functions that are likely involved in the complex mechanisms of cancer progression. We have recently demonstrated that the upregulation of EMP1 expression facilitates cancer cell migration and invasion through the activation of a small GTPase, Rac1. The inoculation of prostate cancer cells overexpressing EMP1 into nude mice leads to metastasis to the lymph nodes and lungs, indicating that EMP1 contributes to metastasis. Pro-metastatic properties of EMP2 and EMP3 have also been proposed. Thus, targeting EMPs may provide new insights into their clinical utility. Here, we highlight the important aspects of EMPs in cancer biology, particularly invasiveness and metastasis, and describe recent therapeutic approaches.

scholarly journals Proteases Immobilization for In Situ Time-Limited Proteolysis on MALDI Chips

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 833 ◽  
Author(s):  
Rosulek ◽  
Darebna ◽  
Pompach ◽  
Slavata ◽  
Novak
Keyword(s):  
Mass Spectrometry ◽  
Indium Tin Oxide ◽  
Proteolytic Enzymes ◽  
Protein Structures ◽  
Limited Proteolysis ◽  
Covalent Bond ◽  
Maldi Mass Spectrometry ◽  
Clinical Diagnostics ◽  
Oxide Glass

A large number of different enzyme immobilization techniques are used in the field of life sciences, clinical diagnostics, or biotechnology. Most of them are based on a chemically mediated formation of covalent bond between an enzyme and support material. The covalent bond formation is usually associated with changes of the enzymes’ three-dimensional structure that can lead to reduction of enzyme activity. The present work demonstrates a potential of an ambient ion-landing technique to effectively immobilize enzymes on conductive supports for direct matrix-assisted laser desorption/ionization (MALDI) mass spectrometry analyses of reaction products. Ambient ion landing is an electrospray-based technique allowing strong and stable noncovalent and nondestructive enzyme deposition onto conductive supports. Three serine proteolytic enzymes including trypsin, α-chymotrypsin, and subtilisin A were immobilized onto conductive indium tin oxide glass slides compatible with MALDI mass spectrometry. The functionalized MALDI chips were used for in situ time-limited proteolysis of proteins and protein–ligand complexes to monitor their structural changes under different conditions. The data from limited proteolysis using MALDI chips fits to known or predicted protein structures. The results show that functionalized MALDI chips are sensitive, robust, and fast and might be automated for general use in the field of structural biology.

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