caa a22 4500 475743962 CHVBK 20180406123507.0 cr unu---uuuuu 170329e20000801xx s 000 0 eng 10.1023/A:1026553532289 doi (NATIONALLICENCE)springer-10.1023/A:1026553532289 Kinetic Characterization of the Double Mutant R148A/E182S of Glycogen Phosphorylase Kinase Catalytic Subunit: The Role of the Activation Loop [Elektronische Daten] [Vicky Skamnaki, Nikos Oikonomakos] Many protein kinases are activated by phosphorylation in a highly conserved region of their catalytic subunit, termed activation loop. Phosphorylase kinase is constitutively active without the requirement for phosphorylation of residues in the activation loop. The residue which plays an analogous role to the phosphorylatable residues in other protein kinases is Glu182, which makes contacts to a highly conserved Arg148. In turn, Arg148 adjacent to the catalytic Asp149, enabling information to be transmitted from the activation loop to the catalytic machinery. The double mutant R148A/E182S has been kinetically characterized. The mutation resulted in an approximate 16- to 22-fold decrease in the k cat/K m value of the enzyme. The kinetic data, discussed in the light of the structural data from previously determined complexes of the enzyme, lead to the suggestion that the activation loop has a major role in substrate binding but also in correct orientation of the groups participating in catalysis. Plenum Publishing Corporation, 2000 Phosphorylase kinase nationallicence double mutant nationallicence activation loop nationallicence catalytic mechanism nationallicence Skamnaki Vicky Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, 11635, Athens, Greece aut Oikonomakos Nikos Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, 11635, Athens, Greece aut Journal of Protein Chemistry Kluwer Academic Publishers-Plenum Publishers 19/6(2000-08-01), 499-505 0277-8033 19:6<499 2000 19 10930 https://doi.org/10.1023/A:1026553532289 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1026553532289 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Skamnaki Vicky Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, 11635, Athens, Greece aut NATIONALLICENCE 700 1- Oikonomakos Nikos Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, 11635, Athens, Greece aut NATIONALLICENCE 773 0- Journal of Protein Chemistry Kluwer Academic Publishers-Plenum Publishers 19/6(2000-08-01), 499-505 0277-8033 19:6<499 2000 19 10930 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer