Illarion Turko

Research Chemist

Turko Group

Contact

Email: iturko@umd.edu

Call: (240) 314-6257

Education

  • Research Assistant Professor, UT-Houston Medical School, Houston, TX, 1999-2005
  • Postdoctoral Fellow, Vanderbilt University, Nashville, TN, 1992–1999
  • Ph.D. Biochemistry, Institute of Bioorganic Chemistry, Minsk, Belarus, 1987      
  • B.S. Biochemistry, Byelorussian State University, Minsk, Belarus, 1981

Profile

Proteins have multiple clinical applications--as biomarkers, therapeutics, and components of various biomaterials. All of these applications rely on accurate protein identification and quantification. Dr. Illarion Turko’s research focuses on the development of mass spectrometry measurements and protocols to quantitatively assess the concentrations of targeted proteins and their isoforms in clinically relevant biological samples.

Size exclusion chromatography separation of serum EVs. Mass spectrometry analysis shows a percent recovery of various apolipoproteins, major serum proteins, and EV-specific proteins in void volume fraction. Overall, the data suggest that SEC is an efficient step for initial EV purification (Wang and Turko. 2018. J. Proteome Research).

CURRENT RESEARCH

Proteomic Toolbox to Standardize Purification of Extracellular Vesicles

Extracellular vesicles (EVs) are stable membrane structures that can deliver their cargo remotely and regulate fundamental cellular responses, and EV-based therapeutics are heavily promoted by the biopharmaceutical industry. Pure EVs are needed to unambiguously define their functions; however, because of their low abundance, obtaining pure samples of EVs remains a challenge.

Dr. Turko’s group is working on the development of a quantitative mass spectrometry method to simultaneously measure concentrations of several groups of EV-specific proteins and non-EV proteins. They propose that this approach will provide a toolbox for evaluation of purification protocols to provide a better understanding of their prospects and limitations.

Scheme of the peptide-binding assay for quantitation of mAb aggregates.

Assessing Morphology of Monoclonal Antibody (mAb) Aggregation

Many environmental factors can lead to aggregation of mAbs. The final state and form of aggregation seem to depend on the aggregation pathway. The extent to which different forms of mAb aggregates impact biological activity and the risk of immunogenicity is poorly understood, primarily because of the limitations of existing measurement techniques. Current techniques assess the size and number of aggregates, but not aggregate morphology. Dr. Turko’s team reasoned that protein-protein interfaces that are nonexistent in monomeric mAbs, but present in aggregated mAbs, could be targets for selective, high affinity, short peptide reagents.

This idea prompted the use of peptide phage display technology, a powerful tool in the identification of ligands with novel functions. Peptides bound to aggregate interfaces can be selected from a complex mixture of billions of displayed peptides on phage, and then further enriched through a ‘bio-panning’ process. Once identified, the selected peptides can be used for developing quantitative methods to assess the morphology of mAb aggregation. A proof-of-principle paper has been recently published (Cheung et al. 2017. Scientific Reports).

Publications
2021
Quantitative proteomic analysis for evaluating affinity isolation of extracellular vesicles.
2020
Quantitative Proteomic Analysis of Biogenesis-Based Classification for Extracellular Vesicles.
A New Approach to Assess mAb Aggregation.
2019
Mass spectrometry enumeration of filamentous M13 bacteriophage.
2018
Proteomic Toolbox To Standardize the Separation of Extracellular Vesicles and Lipoprotein Particles.
2017
Assessment of Extracellular Vesicles Purity Using Proteomic Standards.
Cytochrome P450 27A1 Deficiency and Regional Differences in Brain Sterol Metabolism Cause Preferential Cholestanol Accumulation in the Cerebellum.
A new approach to quantification of mAb aggregates using peptide affinity probes.
2016
Mapping of the Allosteric Site in Cholesterol Hydroxylase CYP46A1 for Efavirenz, a Drug That Stimulates Enzyme Activity.
QconCAT: Internal Standard for Protein Quantification.
2015
QUANTITY: An Isobaric Tag for Quantitative Glycomics.
Quantification of Borrelia burgdorferi Membrane Proteins in Human Serum: A New Concept for Detection of Bacterial Infection.
Histone post-translational modifications in frontal cortex from human donors with Alzheimer's disease.
Histone H3 Ser57 and Thr58 phosphorylation in the brain of 5XFAD mice.
Quantification of histone deacetylase isoforms in human frontal cortex, human retina, and mouse brain.
Quantitative performance of internal standard platforms for absolute protein quantification using multiple reaction monitoring-mass spectrometry.
Quantifying CD4 receptor protein in two human CD4+ lymphocyte preparations for quantitative flow cytometry.
2014
Natural flanking sequences for peptides included in a quantification concatamer internal standard.
Structural basis for inactivation of Giardia lamblia carbamate kinase by disulfiram.
2013
Determining carbapenemase activity with 18O labeling and targeted mass spectrometry.