Modification of glyceraldehyde 3-phosphate dehydrogenase activity by adsorption on phospholipid vesicles.
1. The adsorption of [14C]carboxymethylated glyceraldehyde 3-phosphate dehydrogenase to negatively charged liposomes of phsphatidic acid/phosphatidylcholine (3:7, w/w) was investigated. The apparent association constant at I/2 = 60, pH 7.6, was 0.4 X 10(6)M-1. Adsorption decreased as ionic strength and pH were increased. 2. In the presence of negatively charged liposomes, the Km value for glyceraldehyde 3-phosphate of glyceraldehyde 3-phosphate dehydrogenase was increased and Vmax. decreased. In the presence of positively charged liposomes, the Km value for glyceraldehyde 3-phosphate decreased and there was no significant change in Vmax. Addition of Triton X-100 abolished the effect of both positively and negatively charged liposomes on the kinetic properties of the enzyme.
D000327:Adsorption; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008081:Liposomes; D009994:Osmolar Concentration; D010743:Phospholipids / Q000378:metabolism*
D008081:Liposomes; D010743:Phospholipids; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases