M. M. Vorob'ev

Bio: M. M. Vorob'ev is an academic researcher from A. N. Nesmeyanov Institute of Organoelement Compounds. The author has contributed to research in topics: Peptide bond & Hydrolysis. The author has an hindex of 10, co-authored 32 publications receiving 284 citations. Previous affiliations of M. M. Vorob'ev include Russian Academy of Sciences.

Monitoring of Demasking of Peptide Bonds During Proteolysis by Analysis of the Apparent Spectral Shift of Intrinsic Protein Fluorescence

Abstract: Demasking of peptide bonds during proteolysis of β-casein and β-lactoglobulin by trypsin was monitored by the measurement of the overall spectral shift of intrinsic protein fluorescence. A clear shift of the apparent emission maxima from approximately 340–345 nm to 355–360 nm during proteolysis was observed, with a time course, which follows protein degradation and structural opening. In contrast to procedures using extrinsic fluorescence labels, this label-free procedure does not bear the risk of structural alterations. It is easy to perform, fast, and has a relatively high accuracy of determination. Proteolysis was modelled as simple two-step process with consecutive demasking and hydrolysis stages. It was shown that the fluorescence shift can be attributed to the demasking stage. Formally, kinetics of the peptide bond demasking obeys a first-order kinetic law. Both the theoretical simulations and experiment are in accordance giving the similar dependences of the hydrolysis degree on the degree of peptide bond demasking.

Kinetics of peptide bond demasking in enzymatic hydrolysis of casein substrates

Abstract: Proteolysis of casein substrates includes demasking stage, the transition of masked bonds to the demasked stage, where peptide bonds become accessible to the enzyme attack. Therefore, proteolysis was regarded as a two-stage process with consequent demasking and hydrolysis stages. When demasking process is kinetically significant, the peptide bonds are hydrolysed with some lag. It was shown both by theoretical simulations and experimentally that the increase of amino nitrogen can be a non-monotonous function of the hydrolysis degree or proteolysis time. The non-monotonously dependence was found for chymotryptic proteolysis of β-casein, while for α-casein the monotonous dependence was obtained. This was treated as an indication of the prevalence of the hydrophobically induced masking effect for β-casein. For the proteolysis of β-casein by wild-type and engineered trypsins, the kinetic analysis allowed us to conclude that demasking stage was initiated by the splitting of the main peptide chain, which compact conformation was initially stabilized by the interaction of hydrophobic regions of peptide chain.

Kinetic description of proteolysis. Part 2. Substrate regulation of peptide bond demasking and hydrolysis. Liquid chromatography of hydrolyzates.

Abstract: Lower peptides and amino acids in hydrolyzates of casein obtained with protosubtilin were determined using high pressure liquid chromatography (HPLC). The dependences of product concentrations in hydrolyzates produced at different substrate concentrations on the degree of hydrolysis were obtained. With an increase of the substrate concentration the real type of proteolysis changes from “zipper” to “one-by-one”. This result supports the assumption that the substrate proteolysis regulation is realized through the change in the ratio of the rates of peptide bond demasking to those of peptide bond hydrolysis. The description of protein hydrolysis kinetics needs a more complex approach than that based on MICHAELIS-MENTEN equation 111. The above approach to proteolysis is based specifically on the assumptions that all peptide bonds are hydrolyzed with the same kinetic constants and can be freely attacked by proteases. In fact, these two assumptions are not supported by the experiments [2], and the proteolysis of peptide bonds can be schematically presented as a two-stage successive transformation :

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Molecular imprinting science and technology: a survey of the literature for the years up to and including 2003

Abstract: Molecular imprinting science and technology: a survey of the literature for the years up to and including 2003

Imprinting of synthetic polymers using molecular templates

Abstract: The concept of using a molecular template to generate recognition sites for selective separations or reactions within a polymeric network is an exciting, challenging and far-reaching one. This review seeks to explain and define the concept and its components. It traces the early developments by the pioneers in the field and highlights the important advances made, or the key crossroads passed, in reaching the current state-of-the-art. The various types of templates and template binding which have been explored are reviewed and achievements in re-binding or recognition discussed. Finally, the practicalities of preparing polymer networks imprinted in this manner are dealt with and guidance given in what is currently achievable and what limitations still exist.

Molekulares Prägen (Imprinting) in vernetzten Materialien mit Hilfe von Matrizenmolekülen – auf dem Weg zu künstlichen Antikörpern

Abstract: Kann man in organischen oder anorganischen Polymeren Bindungsstellen ahnlich denen in Antikorpern herstellen, die fur die molekulare Erkennung und unter Umstanden fur die Katalyse geeignet sind? In diesem Beitrag wird uber ein Verfahren zusammenfassend berichtet, bei dem – ahnlich wie man es sich fruher fur die Bildung der Antikorper vorstellte – um ein als Matrize (Schablone, Templat) wirkendes Molekul herum in Gegenwart von wechselwirkenden Monomeren vernetzend polymerisiert wird. Nach dem Abtrennen der Matrize bleibt im Polymer ein Abdruck (Imprint) mit zur Wechselwirkung befahigten Gruppen zuruck, wobei dessen Form und die Anordnung der Haftgruppen in ihm komplementar zur Struktur des Matrizenmolekuls sind. Der Erfolg des Pragevorgangs kann bei Verwendung chiraler Matrizenmolekule anhand der Fahigkeit des Polymers zur Spaltung des Racemats der als Matrize verwendeten Verbindung ermittelt werden. Nach umfangreichen Optimierungen des Verfahrens werden heute in der Chromatographie Trennfaktoren α von 4–8 und Basislinien-Trennungen erhalten. Starkes Interesse gilt auch der Oberflachenpragung von Festkorpern und Monoschichten. Von entscheidender Bedeutung sind in allen Fallen die Struktur der Matrix in den gepragten Materialien und die Funktion der Haftgruppen. Der Mechanismus des Pragens und die molekulare Erkennung von Substraten werden heute schon recht gut verstanden. Zahlreiche praktische Anwendungen derartig hergestellter Produkte werden intensiv bearbeitet. Insbesondere fur die chromatographische Racematspaltung sowie die Verwendung als Chemosensoren, als kunstliche Antikorper und als selektive Katalysatoren sind technische Anwendungen in Sicht. Von besonderem Interesse ist auch die Verwendung entsprechend hergestellter Verbindungen als Enzymmodelle.