Interaction of bovine skeletal muscle lactate dehydrogenase with liposomes. Comparison with the data for the heart enzyme.
The effects of pH, salt concentration and the presence of oxidized and reduced forms of coenzyme on the interaction of skeletal muscle lactate dehydrogenase with the liposomes derived from the total fraction of bovine erythrocyte lipids were investigated by ultracentrifugation and were compared with those results obtained using the heart-rate isoenzyme which we have previously studied. Liposomes are good adsorptive systems for both types of isoenzyme. In the presence of erythrocyte lipid liposomes, bovine muscle and heart lactate dehydrogenases form two kinds of complex: lactate dehydrogenase adsorbed to liposomes and soluble lactate dehydrogenase-phospholipid complexes. Soluble protein-phospholipid complexes reveal different dependences of their stabilities on pH values and it seems that the nature of the binding site in either isozyme is different. In addition, absorption of the isoenzymes on the liposomes also reveals in difference in the effects of NAD and NADH. While the presence of NAD dissociates LDH-H4 from the liposomes and NADH does not influence its adsorption, NAD promotes the binding of LDH-M4, and NADH favors the dissociation.
Dabrowska
A
A
Department of Biochemistry, Academy of Medicine, Wrocław, Poland.
Terlecki
G
G
Gutowicz
J
J
D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002474:Cell-Free System; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008081:Liposomes; D009132:Muscles / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology*; D014461:Ultracentrifugation
D007527:Isoenzymes; D008081:Liposomes; D007770:L-Lactate Dehydrogenase