A unified method for purification of basic proteins

Sanjay Adhikari, Praveen Varma Manthena, Kamal Sajwan, Krishna Kiran Kota, Rabindra Roy

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Protein purification is still very empirical, and a unified method for purifying proteins without an affinity tag is not available yet. In the postgenomic era, functional genomics, however, strongly demands such a method. In this paper we have formulated a unique method that can be applied for purifying any recombinant basic protein from Escherichia coli. Here, we have found that if the pH of the buffer is merely one pH unit below the isoelectric point (p. I) of the recombinant proteins, most of the latter bind to the column. This result supports the Henderson-Hasselbalch principle. Considering that E. coli proteins are mostly acidic, and based on the p. I determined theoretically, apparently all recombinant basic proteins (at least p. I-1 ≥ 6.94) may be purified from E. coli in a single step using a cation-exchanger resin, SP-Sepharose, and a selected buffer pH, depending on the p. I of the recombinant protein. Approximately, two-fifths of human proteome, including many if not all nucleic acid-interacting proteins, have a p. I of 7.94 or higher; virtually all these 12,000 proteins may be purified using this method in a single step.

Original languageEnglish (US)
Pages (from-to)203-206
Number of pages4
JournalAnalytical Biochemistry
Issue number2
StatePublished - May 2010


  • Basic protein
  • Ion-exchange chromatography
  • Protein purification
  • Single step

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology
  • Cell Biology


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