Prev. Article Next Article Table of Contents

Article

A Graphical Approach to Determine the Isoelectric Point and Charge of Small Peptides from pH 0 to 14

Your current credentials do not allow retrieval of the full text.

Purchase the full-text

PDF/HTML,
figures/images,
references and tables,
(where available)

Gabriele D'Andrea and Giuseppe Di Nicolantonio

Department of Biomedical Sciences and Technologies, University of L''Aquila, Coppito 2, I-67100 L''Aquila, Italy

J. Chem. Educ., 2002, 79 (8), p 972

DOI: 10.1021/ed079p972

Publication Date (Web): August 1, 2002

Abstract

The knowledge of a peptide's isoelectric point (pI ) value and its charge value from pH 0 to 14 is of great importance in biology and medicine. Many separation and purification techniques and medical applications depend on the knowledge of these two values. However, students often find it difficult to determine the pI in small peptides with three or more ionizable groups. A graphical approach is here reported with a general linear equation and helpful reminders and rules. Examples of the method are given to determine the pI value in relatively simple peptides and their charge in the pH range from 0 to 14. In applying the general as well as the correlated equations, researchers, students, and teachers should be aware that the actual pK values of ionizable groups in peptides could be quite different from the ones known for the single amino acids from which they are produced. A program list in Pascal is also provided to determine the peptide pI value and its charge in the pH range 0 to 14.

Keywords (Audience):

Upper-Division Undergraduate

Keywords (Domain):

Biochemistry

Keywords (Subject):

Amino Acids

View: Hi-Res PDF | PDF w/ Links

Citing Articles

View all 1 citing articles

Citation data is made available by participants in CrossRef's Cited-by Linking service. For a more comprehensive list of citations to this article, users are encouraged to perform a search in SciFinder.

This article has been cited by 1 ACS Journal articles (1 most recent appear below).

Use of a Spreadsheet To Calculate the Net Charge of Peptides and Proteins as a Function of pH: An Alternative to Using “Canned” Programs To Estimate the Isoelectric Point of These Important Biomolecules
Paul A. Sims
Journal of Chemical Education2010 87 (8), 803-808
- Use of a Spreadsheet To Calculate the Net Charge of Peptides and Proteins as a Function of pH: An Alternative to Using “Canned” Programs To Estimate the Isoelectric Point of These Important Biomolecules
  Paul A. Sims
  Journal of Chemical Education2010 87 (8), 803-808
  An approach is presented that utilizes a spreadsheet to allow students to explore different means of calculating and visualizing how the charge on peptides and proteins varies as a function of pH. In particular, the concept of isoelectric point is ...
  Abstract | Full Text HTML | Hi-Res PDF | PDF w/ Links