Structural-functional relationships in pig heart AMP-deaminase in the presence of ATP, orthophosphate, and phosphatidate bilayers.
The secondary structure of pig heart AMP-deaminase (AMP-d) in the absence and in the presence of orthophosphate or dioleoyl phosphatidic acid (DOPA) or ATP was investigated by FT-IR spectroscopy. While the latter substance activates the enzyme, orthophosphate is a well-known negative allosteric effector and DOPA exerts a noncompetitive inhibition on AMP-deaminase. Small changes in the secondary structure of AMP-d were induced by the above mentioned substances. Only DOPA reduced the thermal stability of AMP-d and avoided protein intermolecular interactions suggesting structural-functional relationships in AMP-d in the presence of the above substances and a possible role of phosphatidic acid in the subtle regulation of AMP-d activity by temporary binding of the enzyme to cellular membranes.
Tanfani
F
F
Institute of Biochemistry, University of Ancona, Ancona, Via Ranieri, 60131, Italy. Tanfani@popcsi.unian.it
Kulawiak
D
D
Kossowska
E
E
Preis
J P
JP
Zydowo
M M
MM
Sarkissova
E
E
Bertoli
E
E
Wozniak
M
M
D000659:AMP Deaminase / Q000737:chemistry / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D004795:Enzyme Stability; D006358:Hot Temperature; D008051:Lipid Bilayers; D009206:Myocardium / Q000201:enzymology*; D010710:Phosphates / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism*; D011487:Protein Conformation; D017550:Spectroscopy, Fourier Transform Infrared; D013329:Structure-Activity Relationship; D013552:Swine
D008051:Lipid Bilayers; D010710:Phosphates; D010712:Phosphatidic Acids; D000255:Adenosine Triphosphate; D000659:AMP Deaminase