Effects of anoxia on protein phosphatase in turtle organs: purification and properties of protein phosphatase type-1 from turtle liver

Arch Biochem Biophys. 1995 Feb 1;316(2):836-43. doi: 10.1006/abbi.1995.1112.


Protein phosphatase type 1 (PP-1) was analyzed in organs of the red-eared slider turtle, Trachemys scripta elegans, a species capable of long-term anoxia survival. During anoxic submergence at 7 degrees C, PP-1 activity in liver rapidly decreased to 63% of the control value within the first hour and remained suppressed over the subsequent 20 h of anoxia. PP-1 activity was also suppressed in red skeletal muscle during anoxia and dropped transiently (after 1 h) in brain but did not change in heart or white muscle. PP-1 was purified from turtle liver using polyethylene glycol fractionation and chromatography on DEAE-cellulose, blue dextran, Sephacryl S-200, and ADP-agarose. A 3000-fold purification was achieved with a final specific activity of 3156 nmol released min-1 mg protein-1 using 32P-labeled phosphorylase a as the substrate. Turtle liver PP-1 was a monomer of molecular mass 37 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis or 38 +/- 2 kDa by Sephacryl S-200 gel filtration. The enzyme was inhibited by okadaic acid (Ki 12.6 +/- 1.4 nM) and AMP (Ki 23 +/- 2 microM) as well as by ADP, ATP, and IMP. Regulation of liver PP-1 appears to be an integral part of anoxia-induced changes in liver glycogenolysis and metabolic rate suppression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Monophosphate / pharmacology
  • Animals
  • Brain / enzymology
  • Brain / physiology
  • Dose-Response Relationship, Drug
  • Ethers, Cyclic / pharmacology
  • Heart / physiology
  • Hypoxia / metabolism*
  • Liver / enzymology
  • Liver / physiology*
  • Muscle, Skeletal / enzymology
  • Muscle, Skeletal / physiology
  • Myocardium / enzymology
  • Okadaic Acid
  • Phosphoprotein Phosphatases / antagonists & inhibitors
  • Phosphoprotein Phosphatases / drug effects
  • Phosphoprotein Phosphatases / isolation & purification
  • Phosphoprotein Phosphatases / metabolism*
  • Tissue Distribution
  • Turtles / physiology*


  • Ethers, Cyclic
  • Okadaic Acid
  • Adenosine Monophosphate
  • Phosphoprotein Phosphatases