Description
Apolipoprotein H (Apo-H), previously known as ┑2-glycoprotein I and beta-2 glycoprotein I, is a 38 kDa multifunctional apolipoprotein that in humans is encoded by the APOH gene[citation needed]. One of its functions is to bind cardiolipin. When bound the structure of cardiolipin and Apo-H both undergo large changes in structure. Within the structure of Apo-H is a stretch of positively charged amino acids (protein sequence positions 282-287), Lys-Asn-Lys-Glu-Lys-Lys, are involved in phospholipid binding (See image on right). Apo-H has a complex involvement in agglutination, it appears to alter adenosine diphosphate (ADP) mediated agglutination of platelets. Normally Apo-H assumes an anti-coagulation activity in serum (by inhibiting coagulation factors); however, changes in blood factors can result of a reversal of that activity