Characterization of pyruvate kinase from the anoxia tolerant turtle, Trachemys scripta elegans: a potential role for enzyme methylation during metabolic rate depression
Background Pyruvate kinase (PK) is responsible for the final reaction in glycolysis. As PK is a glycolytic control point, the analysis of PK posttranslational modifications (PTM) and kinetic changes reveals a key piece of the reorganization of energy metabolism in an anoxia tolerant vertebrate. Meth...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
PeerJ Inc.
2018-06-01
|
| Series: | PeerJ |
| Subjects: | |
| Online Access: | https://peerj.com/articles/4918.pdf |
| _version_ | 1827606549043871744 |
|---|---|
| author | Amanda M.S. Mattice Isabelle A. MacLean Christine L. Childers Kenneth B. Storey |
| author_facet | Amanda M.S. Mattice Isabelle A. MacLean Christine L. Childers Kenneth B. Storey |
| author_sort | Amanda M.S. Mattice |
| collection | DOAJ |
| description | Background Pyruvate kinase (PK) is responsible for the final reaction in glycolysis. As PK is a glycolytic control point, the analysis of PK posttranslational modifications (PTM) and kinetic changes reveals a key piece of the reorganization of energy metabolism in an anoxia tolerant vertebrate. Methods To explore PK regulation, the enzyme was isolated from red skeletal muscle and liver of aerobic and 20-hr anoxia-exposed red eared-slider turtles (Trachemys scripta elegans). Kinetic analysis and immunoblotting were used to assess enzyme function and the corresponding covalent modifications to the enzymes structure during anoxia. Results Both muscle and liver isoforms showed decreased affinity for phosphoenolpyruvate substrate during anoxia, and muscle PK also had a lower affinity for ADP. I50 values for the inhibitors ATP and lactate were lower for PK from both tissues after anoxic exposure while I50 L-alanine was only reduced in the liver. Both isozymes showed significant increases in threonine phosphorylation (by 42% in muscle and 60% in liver) and lysine methylation (by 43% in muscle and 70% in liver) during anoxia which have been linked to suppression of PK activity in other organisms. Liver PK also showed a 26% decrease in tyrosine phosphorylation under anoxia. Discussion Anoxia responsive changes in turtle muscle and liver PK coordinate with an overall reduced activity state. This reduced affinity for the forward glycolytic reaction is likely a key component of the overall metabolic rate depression that supports long term survival in anoxia tolerant turtles. The coinciding methyl- and phospho- PTM alterations present the mechanism for tissue specific enzyme modification during anoxia. |
| first_indexed | 2024-03-09T06:39:51Z |
| format | Article |
| id | doaj.art-09d18186078a4716b3e4d3ce8563815d |
| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T06:39:51Z |
| publishDate | 2018-06-01 |
| publisher | PeerJ Inc. |
| record_format | Article |
| series | PeerJ |
| spelling | doaj.art-09d18186078a4716b3e4d3ce8563815d2023-12-03T10:52:00ZengPeerJ Inc.PeerJ2167-83592018-06-016e491810.7717/peerj.4918Characterization of pyruvate kinase from the anoxia tolerant turtle, Trachemys scripta elegans: a potential role for enzyme methylation during metabolic rate depressionAmanda M.S. Mattice0Isabelle A. MacLean1Christine L. Childers2Kenneth B. Storey3Institute of Biochemistry, Department of Biology, Carleton University, Ottawa, CanadaInstitute of Biochemistry, Department of Biology, Carleton University, Ottawa, CanadaInstitute of Biochemistry, Department of Biology, Carleton University, Ottawa, CanadaInstitute of Biochemistry, Department of Biology and Chemistry, Carleton University, Ottawa, CanadaBackground Pyruvate kinase (PK) is responsible for the final reaction in glycolysis. As PK is a glycolytic control point, the analysis of PK posttranslational modifications (PTM) and kinetic changes reveals a key piece of the reorganization of energy metabolism in an anoxia tolerant vertebrate. Methods To explore PK regulation, the enzyme was isolated from red skeletal muscle and liver of aerobic and 20-hr anoxia-exposed red eared-slider turtles (Trachemys scripta elegans). Kinetic analysis and immunoblotting were used to assess enzyme function and the corresponding covalent modifications to the enzymes structure during anoxia. Results Both muscle and liver isoforms showed decreased affinity for phosphoenolpyruvate substrate during anoxia, and muscle PK also had a lower affinity for ADP. I50 values for the inhibitors ATP and lactate were lower for PK from both tissues after anoxic exposure while I50 L-alanine was only reduced in the liver. Both isozymes showed significant increases in threonine phosphorylation (by 42% in muscle and 60% in liver) and lysine methylation (by 43% in muscle and 70% in liver) during anoxia which have been linked to suppression of PK activity in other organisms. Liver PK also showed a 26% decrease in tyrosine phosphorylation under anoxia. Discussion Anoxia responsive changes in turtle muscle and liver PK coordinate with an overall reduced activity state. This reduced affinity for the forward glycolytic reaction is likely a key component of the overall metabolic rate depression that supports long term survival in anoxia tolerant turtles. The coinciding methyl- and phospho- PTM alterations present the mechanism for tissue specific enzyme modification during anoxia.https://peerj.com/articles/4918.pdfEnzyme regulationAnoxiaGlycolysisPosttranslational modificationsPyruvate kinaseTrachemys scripta elegans |
| spellingShingle | Amanda M.S. Mattice Isabelle A. MacLean Christine L. Childers Kenneth B. Storey Characterization of pyruvate kinase from the anoxia tolerant turtle, Trachemys scripta elegans: a potential role for enzyme methylation during metabolic rate depression PeerJ Enzyme regulation Anoxia Glycolysis Posttranslational modifications Pyruvate kinase Trachemys scripta elegans |
| title | Characterization of pyruvate kinase from the anoxia tolerant turtle, Trachemys scripta elegans: a potential role for enzyme methylation during metabolic rate depression |
| title_full | Characterization of pyruvate kinase from the anoxia tolerant turtle, Trachemys scripta elegans: a potential role for enzyme methylation during metabolic rate depression |
| title_fullStr | Characterization of pyruvate kinase from the anoxia tolerant turtle, Trachemys scripta elegans: a potential role for enzyme methylation during metabolic rate depression |
| title_full_unstemmed | Characterization of pyruvate kinase from the anoxia tolerant turtle, Trachemys scripta elegans: a potential role for enzyme methylation during metabolic rate depression |
| title_short | Characterization of pyruvate kinase from the anoxia tolerant turtle, Trachemys scripta elegans: a potential role for enzyme methylation during metabolic rate depression |
| title_sort | characterization of pyruvate kinase from the anoxia tolerant turtle trachemys scripta elegans a potential role for enzyme methylation during metabolic rate depression |
| topic | Enzyme regulation Anoxia Glycolysis Posttranslational modifications Pyruvate kinase Trachemys scripta elegans |
| url | https://peerj.com/articles/4918.pdf |
| work_keys_str_mv | AT amandamsmattice characterizationofpyruvatekinasefromtheanoxiatolerantturtletrachemysscriptaelegansapotentialroleforenzymemethylationduringmetabolicratedepression AT isabelleamaclean characterizationofpyruvatekinasefromtheanoxiatolerantturtletrachemysscriptaelegansapotentialroleforenzymemethylationduringmetabolicratedepression AT christinelchilders characterizationofpyruvatekinasefromtheanoxiatolerantturtletrachemysscriptaelegansapotentialroleforenzymemethylationduringmetabolicratedepression AT kennethbstorey characterizationofpyruvatekinasefromtheanoxiatolerantturtletrachemysscriptaelegansapotentialroleforenzymemethylationduringmetabolicratedepression |