The Periodic Loss of Metabolically Unstable DNA from Newly Replicated DNA of Mouse L Cells

The kinetic constants for human very low density lipoproteins (VLDL) of membrane-supported lipoprotein lipase (LPL) of the rat were studied. The VLDL substrate (Sf20-400) was obtained from the plasma of healthy human subjects. with normolipidemia and with normal patterns of VLDL apoprotein peptides in isoelectric focusing electrophoretogram. Triglycerides of human VLDL were hydrolyzed by LPL on the vasclar surface of the isolated rat heart. The calculated maximal reaction velocity (Vmax) and the apparent Michaelis constant (Km) were 0.037±0.006μmol min^-1ml^-1 and 0.060±0.004mM (Mean±S.D.), respectively. These values were very close to the corresponding values obtained using rat VLDL as a substrate. This system provides a means to study possible kinetic abnormalities of the triglyceride-rich lipoproteins on the vascular surface of the heart of hyperlipidemic patients.

^3H-thymidine incorporation

unstable DNA

hydroxyurea