title: AMP-deaminase from hen stomach smooth muscle--physico-chemical properties of the enzyme.
abstract: AMP-deaminase from hen stomach smooth muscle was isolated and physico-chemical properties of the purified enzyme were investigated. The enzyme had an activity optimum at pH 6.5, and poorly deaminated the substrate analogues tested. At optimum pH (6.5), in the absence of regulatory ligands (control conditions), the enzyme manifested hyperbolic substrate-saturation kinetics with half-saturation constant (S(0.5)) of about 4.5 mM. Additions of adenine nucleotide effectors (ATP, ADP) activated the enzyme strongly at all the concentrations tested, diminishing significantly the value of S(0.5) constant. In contrast, the regulatory effect of orthophosphate was variable, and depended on the orthophosphate concentration used. The molecular mass of the enzyme subunit determined in SDS/PAG electrophoresis was about of 37kDa. The obtained results suggest that in different types of hen muscle, similarly as in humans and rats, expression of AMP-deaminase is under the control of independent genes.
authors.affiliation: Department of Biochemistry, Medical University of Gdansk, Gdańsk, Poland. aswiec@amg.gda.pl
authors.forename: Anna
authors.initials: A
authors.lastname: Swieca
authors.forename: Iwona
authors.initials: I
authors.lastname: Rybakowska
authors.forename: Anna
authors.initials: A
authors.lastname: Koryziak
authors.forename: Jerzy
authors.initials: J
authors.lastname: Klimek
authors.forename: Krystian
authors.initials: K
authors.lastname: Kaletha
mesh_terms: D000659:AMP Deaminase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002645:Chickens; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009130:Muscle, Smooth / Q000201:enzymology*; D051381:Rats; D013270:Stomach / Q000201:enzymology*
chemical_list: D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000659:AMP Deaminase