载脂蛋白J的结构与功能

Structure and Function of Apolipoprotein

载脂蛋白Ｊ（ａｐｏＪ）是１９９０年从人血浆ＨＤＬ中新分离出的一种酸性糖蛋白，分子量７００００，由α及β亚基通过二硫键相连而成．通过ａｐｏＪｃＤＮＡ已确定了ａｐｏＪ４２７个氨基酸残基的序列．ａｐｏＪ含双性α螺旋及结合肝素的结构域，可与脂质结合成脂蛋白．ａｐｏＪｍＲＮＡ广泛分布于全身各组织，以脑、卵巢、睾丸及肝脏含量最多．ａｐｏＪ的功能可能有：结合与转运脂质；抑制补体Ｃ８及Ｃ９的激活；参与精子的成熟等。

polipoprotein J (apo J) has been purifiedfrom human plasma HDL and characterized byde Silva et al in 1990. Apo J is a 70kD glyco-protein, comprised of two disulfide-linked sub-units designated apo Ja (34-36kD) and apo Jβ(36-39kD) . The sequence of the 427 aminoacid residues of apo J was deduced by thecDNA cloning and sequencing. The predicteda helical regions of apo J indicated that three ofthese could generate amphiphilic α helices, andmay be lipid - bind domains in apo J . Apo JmRNA was expressed in relatively high levelsin brain . ovary . testis and liver . Apo J isunique among previous characterized humanapolipoproteins in its structure and tissue dis-tribution. The function of apo J is thought tobe involved in a variety of physiological pro-cesses. including bind and transport lipids.regulation of complement function and spermmaturation etc.