Date of Award
Master of Science
Ferroxidase-II was definitely identified as a lipoprotein. Cholesterol and phospholipids remained tightly associated with the ferroxidase-II protein following extensive purification. Quantitative analysis showed that it is a high-density lipoprotein. Thin-layer chromatographic analyses indicated that phosphatidylcholine accounts for the majority of the bound phospholipid with lysophosphatidyl choline and sphingomyel in accounting for the remaining phospholipid.
Treatment of purified ferroxidase-II with phospholipase C or A resulted in a loss of ferroxidase activity which paralleled the hydrolysis of phospholipid. Phospholipid D treatment also resulted in the loss of ferroxidase activity, yet the loss was not as great as with other phospholipases. A lipid-depleted form of ferroxidase-II was prepared by acetone extraction, or gel -filtration following treatment with phospholipase C. However, hydrolysis, not removal , of the lipid was sufficient for the loss of ferroxidase activity.
Disc-gel electrophoresis and protein elution patterns from gel filtration columns of the native and lipid-depleted ferroxidase-II demonstrated that no gross structural changes occur during lipid depletion. The loss of copper accompanied lipid-depletion. The loss of copper explained the inactivation of ferroxidase-II occurring on hydrolysis and removal of lipids. Reconstitution studies with lipid depleted ferroxidase-II indicated that the changes occurring during hydrolvsis and removal of the lipids were not readily reversible.
Sung, Christine Shih Ming, "Ferroxidase-II: a blood serum lipo-protein" (1973). Master's Theses. 1075.