Nikolay Kochev

Dr. Nikolay Kochev

orcid

Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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7 March 2017 in Journal of Cheminformatics
Verified
Journal Article
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JSJiangming Sun
Jiangming Sun
Nina JeliazkovaNina Jeliazkova
Nina Jeliazkova
VCVladimir Chupakhin
Vladimir Chupakhin
JGJose-Felipe Golib-Dzib
Jose-Felipe Golib-Dzib
OEOla Engkvist
Ola Engkvist
HCHongming Chen
Hongming Chen
Chemogenomics data generally refers to the activity data of chemical compounds on an array of protein targets and represents an important source of information for building in silico target prediction models. The increasing volume of chemogenomics data offers exciting opportunities to build models based on Big Data. Preparing a high quality data set is a vital step in realizing this goal and this work aims to compile such a comprehensive chemogenomics dataset. This dataset comprises over 70 million SAR data points from publicly available databases (PubChem and ChEMBL) including structure, target information and activity annotations. Our aspiration is to create a useful chemogenomics resource reflecting industry-scale data not only for building predictive models of in silico polypharmacology and off-target effects but also for the validation of cheminformatics approaches in general.

23 October 2018 in Mutagenesis
Verified
Journal Article
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MHMasamitsu Honma
Masamitsu Honma
AKAiri Kitazawa
Airi Kitazawa
ACAlex Cayley
Alex Cayley
RWRichard V Williams
Richard V Williams
CBChris Barber
Chris Barber
JRJames Rathman
James Rathman
The International Conference on Harmonization (ICH) M7 guideline allows the use of in silico approaches for predicting Ames mutagenicity for the initial assessment of impurities in pharmaceuticals. This is the first international guideline that addresses the use of quantitative structure–activity relationship (QSAR) models in lieu of actual toxicological studies for human health assessment. Therefore, QSAR models for Ames mutagenicity now require higher predictive power for identifying mutagenic chemicals. To increase the predictive power of QSAR models, larger experimental datasets from reliable sources are required. The Division of Genetics and Mutagenesis, National Institute of Health Sciences (DGM/NIHS) of Japan recently established a unique proprietary Ames mutagenicity database containing 12140 new chemicals that have not been previously used for developing QSAR models. The DGM/NIHS provided this Ames database to QSAR vendors to validate and improve their QSAR tools. The Ames/QSAR International Challenge Project was initiated in 2014 with 12 QSAR vendors testing 17 QSAR tools against these compounds in three phases. We now present the final results. All tools were considerably improved by participation in this project. Most tools achieved >50% sensitivity (positive prediction among all Ames positives) and predictive power (accuracy) was as high as 80%, almost equivalent to the inter-laboratory reproducibility of Ames tests. To further increase the predictive power of QSAR tools, accumulation of additional Ames test data is required as well as re-evaluation of some previous Ames test results. Indeed, some Ames-positive or Ames-negative chemicals may have previously been incorrectly classified because of methodological weakness, resulting in false-positive or false-negative predictions by QSAR tools. These incorrect data hamper prediction and are a source of noise in the development of QSAR models. It is thus essential to establish a large benchmark database consisting only of well-validated Ames test results to build more accurate QSAR models.

27 July 2015 in Beilstein Journal of Nanotechnology
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Journal Article
Open access
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Nina JeliazkovaNina Jeliazkova
Nina Jeliazkova
CCCharalampos Chomenidis
Charalampos Chomenidis
PDPhilip Doganis
Philip Doganis
BFBengt Fadeel
Bengt Fadeel
RGRoland Grafström
Roland Grafström
EWEgon Willighagen
Egon Willighagen
Background:The NanoSafety Cluster, a cluster of projects funded by the European Commision, identified the need for a computational infrastructure for toxicological data management of engineered nanomaterials (ENMs). Ontologies, open standards, and interoperable designs were envisioned to empower a harmonized approach to European research in nanotechnology. This setting provides a number of opportunities and challenges in the representation of nanomaterials data and the integration of ENM information originating from diverse systems. Within this cluster, eNanoMapper works towards supporting the collaborative safety assessment for ENMs by creating a modular and extensible infrastructure for data sharing, data analysis, and building computational toxicology models for ENMs.Results:The eNanoMapper database solution builds on the previous experience of the consortium partners in supporting diverse data through flexible data storage, open source components and web services. We have recently described the design of the eNanoMapper prototype database along with a summary of challenges in the representation of ENM data and an extensive review of existing nano-related data models, databases, and nanomaterials-related entries in chemical and toxicogenomic databases. This paper continues with a focus on the database functionality exposed through its application programming interface (API), and its use in visualisation and modelling. Considering the preferred community practice of using spreadsheet templates, we developed a configurable spreadsheet parser facilitating user friendly data preparation and data upload. We further present a web application able to retrieve the experimental data via the API and analyze it with multiple data preprocessing and machine learning algorithms.Conclusion:We demonstrate how the eNanoMapper database is used to import and publish online ENM and assay data from several data sources, how the “representational state transfer” (REST) API enables building user friendly interfaces and graphical summaries of the data, and how these resources facilitate the modelling of reproducible quantitative structure–activity relationships for nanomaterials (NanoQSAR).

20 May 2021 in Nature Nanotechnology
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Journal Article
Closed access
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Nina JeliazkovaNina Jeliazkova
Nina Jeliazkova
Margarita D. ApostolovaMargarita D. Apostolova
Margarita D. Apostolova
CACristina Andreoli
Cristina Andreoli
FBFlavia Barone
Flavia Barone
ABAndrew Barrick
Andrew Barrick
PNPenny Nymark
Penny Nymark

18 August 2022 in Nature Nanotechnology
Verified
Journal Article
Closed access
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EWEwelina Wyrzykowska
Ewelina Wyrzykowska
Alicja MikołajczykAlicja Mikołajczyk
Alicja Mikołajczyk
Iseult LynchIseult Lynch
Iseult Lynch
Nina JeliazkovaNina Jeliazkova
Nina Jeliazkova
NKNikolay Kochev
Nikolay Kochev
Tomasz PuzynTomasz Puzyn
Tomasz Puzyn

12 June 2019 in Frontiers in Chemistry
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Journal Article
Open access
CKChristina de Bruyn Kops
Christina de Bruyn Kops
CSConrad Stork
Conrad Stork
MŠMartin Šícho
Martin Šícho
NKNikolay Kochev
Nikolay Kochev
DSDaniel Svozil
Daniel Svozil
Johannes KirchmairJohannes Kirchmair
Johannes Kirchmair
Computational prediction of xenobiotic metabolism can provide valuable information to guide the development of drugs, cosmetics, agrochemicals, and other chemical entities. We have previously developed FAME 2, an effective tool for predicting sites of metabolism (SoMs). In this work, we focus on the prediction of the chemical structures of metabolites, in particular metabolites of xenobiotics. To this end, we have developed a new tool, GLORY, which combines SoM prediction with FAME 2 and a new collection of rules for metabolic reactions mediated by the cytochrome P450 enzyme family. GLORY has two modes: MaxEfficiency and MaxCoverage. For MaxEfficiency mode, the use of predicted SoMs to restrict the locations in the molecule at which the reaction rules could be applied was explored. For MaxCoverage mode, the predicted SoM probabilities were instead used to develop a new scoring approach for the predicted metabolites. With this scoring approach, GLORY achieves a recall of 0.83 and can predict at least one known metabolite within the top three ranked positions for 76% of the molecules of a new, manually curated test set. GLORY is freely available as a web server at https://acm.zbh.uni-hamburg.de/glory/, and the datasets and reaction rules are provided in the Supplementary Material.