title: Interaction with troponin T from white skeletal muscle restores in white skeletal muscle AMP deaminase those allosteric properties removed by limited proteolysis.
abstract: Limited proteolysis of rabbit skeletal muscle AMP deaminase (AMP aminohydrolase, EC 3.5.4.6) with trypsin results in conversion of the enzyme to a form which is no longer inhibited by ATP and exhibits hyperbolic kinetics even at low K+ concentration and in the absence of ADP. The interaction with troponin T from white skeletal muscle or with the phosphorylated 42-residue N-terminal peptide of troponin T restores in the trypsin-treated AMP deaminase the sensitivity to adenine nucleotides and increases the KA for K+ activation of the enzyme from 1 mM to 12 mM, this effect being diametrically opposite to that exerted by limited proteolysis on the native enzyme. Treatment of the N-terminal peptide of troponin T with alkaline phosphatase abolishes the modulating properties of the peptide, suggesting that phosphorylation-dephosphorylation processes may be involved in the regulation of the enzyme.
mesh_terms: D000659:AMP Deaminase / Q000378:metabolism*; D000469:Alkaline Phosphatase; D007700:Kinetics; D009132:Muscles / Q000201:enzymology*; D009709:Nucleotide Deaminases / Q000378:metabolism*; D010446:Peptide Fragments; D014336:Troponin / Q000378:metabolism*; D020107:Troponin T; D014357:Trypsin
chemical_list: D010446:Peptide Fragments; D014336:Troponin; D020107:Troponin T; D000469:Alkaline Phosphatase; D014357:Trypsin; D009709:Nucleotide Deaminases; D000659:AMP Deaminase