Anaerobiosis and the regulation of glycolytic enzymes in the sea anemoneMetridium senile

✍ Scribed by Michaelidis, Basile ;Storey, Kenneth B.

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 841 KB
• Volume: 256
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402560205

✦ Synopsis

Abstract

The regulation of glycolytic enzymes during anaerobiosis was examined in three tissues, muscular body wall, tentacles, and mesoglia, of the sea anemcme Metridium senile. Anoxia‐induced stable modifications of the activities or kinetic and regulatory properties of glycogen phosphorylase, phosphofructokinase (PFK), and pyruvate kinase (PK), were detected. In the two muscular tissues, anoxia had the greatest effect on the properties of PFK; for PFK in body wall So F6P decreased, K~m~ ATP increased, I~50~ PEP increased, and K~a~ values for AMP and inorganic phosphate increased, compared to PFK in aerobic muscle. In addition, levels of the PFK activator fructose‐2,6‐bisphosphate decreased sharply after 21 hours of anoxia LO amounts 19, 48, and 39% of aerobic control values in body wall, tentacles, and mesoglia, respectively. Anoxia exposure had fewer effects on the properties of PK, and primary control of the enzyme in muscular tissues may reside with allosteric effectors, F1, 6P~2~ activation, and strong L‐alanine inhibition. PK in mesoglia, by contrast, was virtually unaffected by allosteric modifiers but shcwed a 4‐fold decrease in S~0.5~ PEP in anoxia. The results suggest that changes in glycolytic function during anaerobiosis in sea anemones are mediated by covalent modifications of the regulatory enzymes as well as changes in the levels of F2,6P~2~ and other metabolite effectors of the enzymes.