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Involvement of a tyrosine residue in the ADP binding site of creatine kinase. A second‐derivative UV‐spectroscopy study
Author(s) -
Leydier Chantal,
Clottes Eric,
Couthon Fabienne,
Marcillat Olivier,
Vial Christian
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700201811
Subject(s) - tyrosine , chemistry , dissociation constant , residue (chemistry) , creatine kinase , enzyme , binding site , creatine , solvent , dissociation (chemistry) , monomer , nucleotide , stereochemistry , nuclear magnetic resonance spectroscopy , substrate (aquarium) , biochemistry , organic chemistry , biology , receptor , gene , polymer , ecology
Second‐derivative spectroscopy was used to determine the percentage of tyrosine residues that are exposed to solvent in rabbit MM‐creatine kinase. Six residues, among the ten present per monomer, are solvent‐exposed. The presence of creatine in the incubation medium does not modify this value. However, this number is decreased by one when the enzyme is incubated with saturating concentrations of MgADP. A dissociation constant for MgADP can be estimated and the obtained value (0.085 mM) is comparable to the Km for this substrate. Thus, a tyrosine residue is located near the MgADP binding site or is masked during protein conformational change induced by adenyl nucleotide binding.