AMP-deaminase from human term placenta.
AMP-deaminase from human term placenta was chromatographed on a phosphocellulose column and physico-chemical and immunological properties of the purified enzyme were investigated. At physiological pH 7.0, in the absence of regulatory ligands (control conditions) studied AMP-deaminase manifested sigmoid-shaped substrate saturation kinetics, with half-saturation parameter (S0.5) value of about 7 mM. Addition of important allosteric effectors (ATP, ADP or orthophosphate) modified kinetic properties of studied AMP-deaminase, influencing mainly the value of S0.5, parameter. Micromolar concentrations of stearylo-CoA inhibited potently the enzyme making it no longer sensitive towards 1 mM ATP-induced activation. SDS-PAGE electrophoresis of the purified enzyme revealed presence of 68 kDa protein fragment, reacting with anti-(human) liver AMP-deaminase antibodies. Experimental results presented indicate that 'liver type' of AMP-deaminase is an enzyme form present in human term placenta.
Swieca
A
A
Department of Biochemistry, Medical University of Gdansk, Gdansk, Poland.
Rybakowska
I
I
Nagel-Starczynowska
G
G
Kossowska
E
E
Kaletha
K
K
D000659:AMP Deaminase / Q000302:isolation & purification* / Q000378:metabolism; D000494:Allosteric Regulation; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007700:Kinetics; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D013379:Substrate Specificity
D000659:AMP Deaminase