UNIT 3.10 Phosphatases and Kinases

  1. Stanley Tabor

Published Online: 1 MAY 2001

DOI: 10.1002/0471142727.mb0310s00

Current Protocols in Molecular Biology

Current Protocols in Molecular Biology

How to Cite

Tabor, S. 2001. Phosphatases and Kinases. Current Protocols in Molecular Biology. 00:III:3.10:3.10.1–3.10.5.

Author Information

  1. Harvard Medical School, Boston, Massachusetts

Publication History

  1. Published Online: 1 MAY 2001
  2. Published Print: OCT 1987


The reaction conditions and applications of two phosphatases and one kinase are described in this unit. Bacterial alkaline phosphatase (BAP) from E. coli and calf intestine phosphatase (CIP) from veal are commonly used in nucleic acid research. Both enzymes catalyze the hydrolysis of 5′-phosphate residues from DNA, RNA, and ribo- and deoxyribonucleoside triphosphates. The dephosphorylated products possess 5′-hydroxyl termini which can subsequently be radioactively labeled using [γ-32P]ATP and T4 polynucleotide kinase. T4 polynucleotide kinase has 3 activities: the forward reaction efficiently catalyzes the transfer of the terminal (γ) phosphate of ATP to the 5′-hydroxyl termini of DNA and RNA. The exchange reaction catalyzes the exchange of 5'-terminal phosphates. Lastly, T4 polynucleotide kinase is a 3′ phosphatase.