Skip to main content

Main menu

  • Home
  • Content
    • Current Issue
    • Past Issues
    • Accepted Articles
    • Email Alerts
    • RSS
    • Terms of Use
  • About PDA JPST
    • JPST Editors and Editorial Board
    • About/Vision/Mission
    • Paper of the Year
  • Author & Reviewer Resources
    • Author Resources / Submit
    • Reviewer Resources
  • JPST Access and Subscriptions
    • PDA Members
    • Institutional Subscriptions
    • Nonmember Access
  • Support
    • Join PDA
    • Contact
    • Feedback
    • Advertising
    • CiteTrack
  • .
    • Visit PDA
    • PDA Letter
    • Technical Reports
    • news uPDATe
    • Bookstore

User menu

  • Register
  • Subscribe
  • My alerts
  • Log in
  • My Cart

Search

  • Advanced search
PDA Journal of Pharmaceutical Science and Technology
  • .
    • Visit PDA
    • PDA Letter
    • Technical Reports
    • news uPDATe
    • Bookstore
  • Register
  • Subscribe
  • My alerts
  • Log in
  • My Cart
PDA Journal of Pharmaceutical Science and Technology

Advanced Search

  • Home
  • Content
    • Current Issue
    • Past Issues
    • Accepted Articles
    • Email Alerts
    • RSS
    • Terms of Use
  • About PDA JPST
    • JPST Editors and Editorial Board
    • About/Vision/Mission
    • Paper of the Year
  • Author & Reviewer Resources
    • Author Resources / Submit
    • Reviewer Resources
  • JPST Access and Subscriptions
    • PDA Members
    • Institutional Subscriptions
    • Nonmember Access
  • Support
    • Join PDA
    • Contact
    • Feedback
    • Advertising
    • CiteTrack
  • Follow pda on Twitter
  • Visit PDA on LinkedIn
  • Visit pda on Facebook
Research ArticleTechnology/Application

An Improved Method of Predicting Extinction Coefficients for the Determination of Protein Concentration

Eric C. Hilario, Alan Stern, Charlie H. Wang, Yenny W. Vargas, Charles J. Morgan, Trevor E. Swartz and Thomas W. Patapoff
PDA Journal of Pharmaceutical Science and Technology March 2017, 71 (2) 127-135; DOI: https://doi.org/10.5731/pdajpst.2016.007120
Eric C. Hilario
1Early Stage Pharmaceutical Development,
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: ehilario@gene.com
Alan Stern
2Late Stage Pharmaceutical Development,
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Charlie H. Wang
1Early Stage Pharmaceutical Development,
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Yenny W. Vargas
3Biostatistics Group, Genentech, Inc.,
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Charles J. Morgan
4Pharma Technical Regulatory, 1 DNA Way, South San Francisco, CA 94080, USA
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Trevor E. Swartz
1Early Stage Pharmaceutical Development,
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Thomas W. Patapoff
1Early Stage Pharmaceutical Development,
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • References
  • Info & Metrics
  • PDF
Loading

Abstract

Concentration determination is an important method of protein characterization required in the development of protein therapeutics. There are many known methods for determining the concentration of a protein solution, but the easiest to implement in a manufacturing setting is absorption spectroscopy in the ultraviolet region. For typical proteins composed of the standard amino acids, absorption at wavelengths near 280 nm is due to the three amino acid chromophores tryptophan, tyrosine, and phenylalanine in addition to a contribution from disulfide bonds. According to the Beer-Lambert law, absorbance is proportional to concentration and path length, with the proportionality constant being the extinction coefficient. Typically the extinction coefficient of proteins is experimentally determined by measuring a solution absorbance then experimentally determining the concentration, a measurement with some inherent variability depending on the method used. In this study, extinction coefficients were calculated based on the measured absorbance of model compounds of the four amino acid chromophores. These calculated values for an unfolded protein were then compared with an experimental concentration determination based on enzymatic digestion of proteins. The experimentally determined extinction coefficient for the native proteins was consistently found to be 1.05 times the calculated value for the unfolded proteins for a wide range of proteins with good accuracy and precision under well-controlled experimental conditions. The value of 1.05 times the calculated value was termed the predicted extinction coefficient. Statistical analysis shows that the differences between predicted and experimentally determined coefficients are scattered randomly, indicating no systematic bias between the values among the proteins measured. The predicted extinction coefficient was found to be accurate and not subject to the inherent variability of experimental methods. We propose the use of a predicted extinction coefficient for determining the protein concentration of therapeutic proteins starting from early development through the lifecycle of the product.

LAY ABSTRACT: Knowing the concentration of a protein in a pharmaceutical solution is important to the drug's development and posology. There are many ways to determine the concentration, but the easiest one to use in a testing lab employs absorption spectroscopy. Absorbance of ultraviolet light by a protein solution is proportional to its concentration and path length; the proportionality constant is the extinction coefficient. The extinction coefficient of a protein therapeutic is usually determined experimentally during early product development and has some inherent method variability. In this study, extinction coefficients of several proteins were calculated based on the measured absorbance of model compounds. These calculated values for an unfolded protein were then compared with experimental concentration determinations based on enzymatic digestion of the proteins. The experimentally determined extinction coefficient for the native protein was 1.05 times the calculated value for the unfolded protein with good accuracy and precision under controlled experimental conditions, so the value of 1.05 times the calculated coefficient was called the predicted extinction coefficient. Comparison of predicted and measured extinction coefficients indicated that the predicted value was very close to the experimentally determined values for the proteins. The predicted extinction coefficient was accurate and removed the variability inherent in experimental methods.

  • Extinction coefficient
  • Protein concentration
  • Absorbance spectrum
  • Absorptivity
  • Chromophores
  • Model compounds
  • © PDA, Inc. 2017
View Full Text

PDA members receive access to all articles published in the current year and previous volume year. Institutional subscribers received access to all content. Log in below to receive access to this article if you are either of these.  

If you are neither or you are a PDA member trying to access an article outside of your membership license, then you must purchase access to this article (below). If you do not have a username or password for JPST, you will be required to create an account prior to purchasing. 

Full issue PDFs are for PDA members only.

Note to pda.org users

The PDA and PDA bookstore websites (www.pda.org and www.pda.org/bookstore) are separate websites from the PDA JPST website. When you first join PDA, your initial UserID and Password are sent to HighWirePress to create your PDA JPST account. Subsequent UserrID and Password changes required at the PDA websites will not pass on to PDA JPST and vice versa. If you forget your PDA JPST UserID and/or Password, you can request help to retrieve UserID and reset Password below.

Log in using your username and password

Forgot your user name or password?

Log in through your institution

You may be able to gain access using your login credentials for your institution. Contact your library if you do not have a username and password.
If your organization uses OpenAthens, you can log in using your OpenAthens username and password. To check if your institution is supported, please see this list. Contact your library for more details.

Purchase access

You may purchase access to this article. This will require you to create an account if you don't already have one.

patientACCESS

patientACCESS - Patients desiring access to articles

Full issue PDFs are for PDA members only. You can join PDA at www.pda.org. 

PreviousNext
Back to top

In This Issue

PDA Journal of Pharmaceutical Science and Technology: 71 (2)
PDA Journal of Pharmaceutical Science and Technology
Vol. 71, Issue 2
March/April 2017
  • Table of Contents
  • Index by Author
Print
Download PDF
Article Alerts
Sign In to Email Alerts with your Email Address
Email Article

Thank you for your interest in spreading the word on PDA Journal of Pharmaceutical Science and Technology.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
An Improved Method of Predicting Extinction Coefficients for the Determination of Protein Concentration
(Your Name) has sent you a message from PDA Journal of Pharmaceutical Science and Technology
(Your Name) thought you would like to see the PDA Journal of Pharmaceutical Science and Technology web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
2 + 7 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.
Citation Tools
An Improved Method of Predicting Extinction Coefficients for the Determination of Protein Concentration
Eric C. Hilario, Alan Stern, Charlie H. Wang, Yenny W. Vargas, Charles J. Morgan, Trevor E. Swartz, Thomas W. Patapoff
PDA Journal of Pharmaceutical Science and Technology Mar 2017, 71 (2) 127-135; DOI: 10.5731/pdajpst.2016.007120

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Share
An Improved Method of Predicting Extinction Coefficients for the Determination of Protein Concentration
Eric C. Hilario, Alan Stern, Charlie H. Wang, Yenny W. Vargas, Charles J. Morgan, Trevor E. Swartz, Thomas W. Patapoff
PDA Journal of Pharmaceutical Science and Technology Mar 2017, 71 (2) 127-135; DOI: 10.5731/pdajpst.2016.007120
Reddit logo Twitter logo Facebook logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • Abstract
    • Introduction
    • Materials and Methods
    • Results and Discussion
    • Summary and Conclusions
    • Conflict of Interest Declaration
    • Acknowledgements
    • References
  • Figures & Data
  • Info & Metrics
  • References
  • PDF

Related Articles

  • No related articles found.
  • PubMed
  • Google Scholar

Cited By...

  • No citing articles found.
  • Google Scholar

More in this TOC Section

  • Design, Development and Validation of a Culture-Independent Nucleic Acid Diagnostics Method for the Rapid Detection and Quantification of the Burkholderia cepacia Complex in Water with an Equivalence to ISO/TS 12869:2019
  • Using Sensitivity Analysis to Simplify the Virus Safety Factor Calculation in the Manufacture of Biopharmaceuticals
  • Rapid Sterility Test Systems in the Pharmaceutical Industry: Applying a Structured Approach to their Evaluation, Validation and Global Implementation
Show more Technology/Application

Similar Articles

Keywords

  • Extinction coefficient
  • Protein concentration
  • Absorbance spectrum
  • Absorptivity
  • Chromophores
  • Model compounds

Readers

  • About
  • Table of Content Alerts/Other Alerts
  • Subscriptions
  • Terms of Use
  • Contact Editors

Author/Reviewer Information

  • Author Resources
  • Submit Manuscript
  • Reviewers
  • Contact Editors

Parenteral Drug Association, Inc.

  • About
  • Advertising/Sponsorships
  • Events
  • PDA Bookstore
  • Press Releases

© 2023 PDA Journal of Pharmaceutical Science and Technology ISSN: 1079-7440

Powered by HighWire