Human Cytochrome P450 2C9 and Its Polymorphic Modifications: Electroanalysis, Catalytic Properties, and Approaches to the Regulation of Enzymatic Activity

Round 1

Reviewer 1 Report

Authors have presented electrochemical measurements of catalytic reactions of CYP2C( and two of its common polymorphic variants. Metabolism of diclofenac was used as a model to test a couple of antioxidants for their impact on the modulation of CYP2C9 activities.

This is an interesting concept and worthy of publication. I have only few minor comments to address before publication.

1. Abstract is a bit uninformative. Authors should remove some details of results to better summarize their findings and include the significance of their study and conclusions in the abstract so that it is a proper summary of the manuscript and its main findings.
2. Some grammar check is needed, for example in the use of "in" and "of" being used incorrectly, but these can perhaps be addressed by the copyeditor.
3. In the presentation of results and discussion, two concepts of the manuscript are getting mixed, one the measurement of catalytic activities by electrochemical method and comparison of mutant activities with WT allele, and second, the concept of modulating the activity by external agents. The authors should separate these a bit and discuss the results as two individual concepts.
4. Some discussion about mechanisms by which the antioxidants may modulate the reactions will be of help. Is it direct binding to P450, or perhaps binding to POR, that is changing the activities? (See the publication by Jensen et al in Nature communication by conformational modulation of POR to change activities of CYPs via biased metabolism). The authors should discuss the potential mechanisms a bit more.

Author Response

We would like to thank you forcareful evaluation of our manuscript and the comments. 

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Research manuscript entitled “Human Cytochrome P450 2C9 and its polymorphic modifications: electroanalysis, catalytic properties, and approaches to the regulation of enzymatic activity” has been written systematically and it can be accepted after minor revision.

• Whether diclofenac undergoes catalysis in argon saturated buffer at the modified electrode?
• The catalysis peak position of the diclofenac overlaps with the SPE/DDAB/P450 2C9 modified electrode in aerobic (-) electrolyte buffer! Whether diclofenac shows oxidation peak or it enhances the oxygen reduction?
• In Fig3, why the applied potential was selected as -0.55 V?
• Mechanism for the electrooxidation of Diclofenac in presence of antioxidants may be discussed

Author Response

We would like to thank you for careful evaluation of our manuscript and the comments. 

Please see the attachment

Author Response File: Author Response.docx