Kinetic study of the action of snake venom phospholipase A/sub 2/ on human serum high density lipoprotein 3. [Crotalus adamanteus]

Journal Article · Sat Apr 10 04:00:00 EST 1976 · J. Biol. Chem.; (United States)

OSTI ID:7263586

Pattnaik, N M; Kezdy, F J; Scanu, A M

The hydrolysis of the phospholipids of intact human serum high density lipoprotein 3 (HDL/sub 3/) by pure ..cap alpha..-phospholipase A/sub 2/ from Crotalus adamanteus was studied by pH-stat titration. The enzyme quantitatively hydrolyzed phosphatidylcholine and phosphatidylethanolamine and left sphingomyelin intact, yielding a stable and water-soluble modified HDL. Lysophospholipids and free fatty acids, the products of hydrolysis, remained in the lipoprotein. When 1 mol of defatted bovine serum albumin/mol of substrate phospholipids was added to the reaction mixture, up to 60 percent of the fatty acids and 85 percent of the lysophospholipids were removed from the modified lipoprotein. The immunological reactivity of the hydrolyzed HDL remained unaltered in both the presence and absence of albumin. The changes in the physical properties of the lipoprotein during hydrolysis were rather small, the most notable being an increase in the hydrated density and in the electrophoretic mobility in alkaline buffers. From the accessibility of the HDL phospholipids to phospholipase A/sub 2/ one concludes that the phosphatidylcholine and phosphatidylethanolamine are located at, or are in rapid equilibrium with, the surface of this lipoprotein. It also appears that these phospholipids are not essential for maintaining the supramolecular properties of the lipoprotein in vitro. Thus the study of the modified HDL should provide valuable information concerning the structure and function of this lipoprotein particularly with regard to the role played by sphingomyelin.

• Research Organization: Univ. of Chicago
• OSTI ID: 7263586
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 251:7; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ALBUMINS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BLOOD SERUM
CHEMICAL REACTIONS
DECOMPOSITION
ENZYMES
ESTERASES
ESTERS
HYDROLASES
HYDROLYSIS
KINETICS
LIPASES
LIPIDS
LIPOPROTEINS
LYSIS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHOLIPIDS
PROTEINS
REACTION KINETICS
REPTILES
SNAKES
SOLVOLYSIS
VENOMS
VERTEBRATES