| Modification Notes |
The Platelet Activating Factor (PAF) Acetylhydrolases catalyze hydrolysis of the sn-2 ester bond of PAF and related pro-inflammatory phospholipids and thus attenuate their bioactivity. The family of PAF Acetylhydrolases include one secreted plasma isozyme and four intracellular proteins. The intra-cellular isozymes are distinguished by differences in their primary sequence, tissue localization, subunit composition, and substrate preferences. The most thoroughly characterized intracellular isoform, Ib, contains two homologous (63% identity) catalytic subunits (a1 and a2), which harbor all the enzyme’s activity, and a regulatory b subunit. The a subunits readily associate with very high affinity to form homodimers, and this dimerization is essential for both stability and catalytic activity. The b subunit is a product of the LIS1 gene, mutations of which cause Miller-Dieker lissencephaly. |