Chapter 10 Lecithin cholesterol acyltransferase
1987; Elsevier BV; Linguagem: Inglês
10.1016/s0167-7306(08)60204-5
ISSN1875-7901
Autores Tópico(s)Lipid metabolism and biosynthesis
ResumoThis chapter highlights lecithin cholesterol acyltransferase (LCAT) enzyme that is responsible for the removal of an acyl chain from lecithin and its transfer to free cholesterol. LCAT is synthesized by the liver and is secreted into plasma where it is present either free or in association with lipoproteins. Its preferred substrates are high-density lipoproteins (HDL), especially in nascent disc form or as the smaller subclasses of spherical HDL particles. Apolipoproteins of HDL (particularly apolipoprotein A-I, apoA-I) activate LCAT, and the HDL core initially stores the cholesterol ester products of the enzymatic reaction. Through its action on HDL, LCAT has the general effect of reducing the free (or unesterified) cholesterol content of lipoproteins and of cell plasma membranes; thus, LCAT participates in the maturation of HDL, changes the distribution of HDL subclasses and their composition, and modifies the lipid composition and overall structure of other lipoproteins. In decreasing the free cholesterol content of lipoproteins, LCAT affects the cholesterol content of membranes, and is involved in the maintenance of membrane structure, and indirectly in determining the levels of total cellular cholesterol.
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