HDL3 is the most excellent substrate of LCAT reaction. 2) Significant relationships of LCAT activities with serum concentrations of LDL, VLDL, cholesterol, triglyceride and phospholipid, and body weight were observed. No significant relationships were observed between the activity and serum concentrations of HDL3 and HDL2. 3) LCAT activities increased in the various secondary hyperlipedemic states. However, the activities remained within normal range in the familial hyperlipidemias. 4) Immunological properties of apolipoproteins were consistent between normal and hyperlipidemic subjects. 5) Amino acid compositions of hyperlipidemic subjects were almost consistent with those of normal subjects. However, significant differences of amino acid compositions were observed in the patients with familial type II and type IV hyperlipidemias with genetic factor, as compaired with those of normal and other hyperlipidemic subjects. 6) Discussions were made about the above-mentioned results. Authors greatly acknowledge Drs. T. Shimizu, M. Iijima, E. Sasa, T. Kinoshita and M. Harada for their cooperations.
