The platelet-activating factor-acetylhydrolase (PAF-AH) is an enzyme which catalyzes the hydrolysis of acetyl ester at the sn-2 position of PAF. The family of PAF-AHs consists of two intracellular isoforms (Ib and II), and one secreted isoform (plasma). These PAF-AHs show different biochemical characteristics and molecular structures. Plasma PAF-AH and intracellular isoform, II degrade not only PAF but also oxidatively fragmented phospholipids with potent biological activities. Among these PAF-AHs, plasma PAF-AH has been the target of many clinical studies in inflammatory diseases, such as asthma, sepsis, and vascular diseases, because the plasma PAF-AH activity in the patients with these diseases is altered when compared with normal individuals. Finding a genetic deficiency in the plasma PAF-AH opened the gate in elucidating the protecting role of this enzyme in inflammatory diseases. The most common loss-of-function mutation, V279F, is found in more than 30% of Japanese subjects (4% homozygous, 27% heterozygous). This single nucleotide polymorphism in plasma PAF-AH and the resulting enzymatic deficiency is thought to be a genetic risk factor in various inflammatory diseases in Japanese subjects. Administration of recombinant plasma PAF-AH or transfer of the plasma PAF-AH gene improves pathology in animal models. Therefore, substitution of plasma PAF-AH would be an effective in the treatment of the patients with the inflammatory diseases and a novel clinical approach. In addition, the detection of polymorphisms in the plasma PAF-AH gene and abnormalities in enzyme activity would be beneficial in the diagnosis of the inflammatory diseases.

中文翻译：

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血浆血小板活化因子-乙酰水解酶（PAF-AH）。

血小板活化因子乙酰水解酶（PAF-AH）是一种催化PAF的sn-2位上的乙酰酯水解的酶。PAF-AH家族由两种细胞内亚型（Ib和II）和一种分泌型亚型（血浆）组成。这些PAF-AH具有不同的生化特性和分子结构。血浆PAF-AH和细胞内同工型II不仅降解PAF，而且还降解具有有效生物学活性的氧化破碎的磷脂。在这些PAF-AH中，血浆PAF-AH已成为炎症性疾病（如哮喘，败血症和血管疾病）的许多临床研究的目标，因为与这些疾病相比，这些疾病患者的血浆PAF-AH活性发生了改变。正常人。在血浆PAF-AH中发现遗传缺陷，为阐明该酶在炎症性疾病中的保护作用打开了大门。在超过30％的日本受试者中发现了最常见的功能丧失突变V279F（4％的纯合子，27％的杂合子）。血浆PAF-AH中的这种单核苷酸多态性和所导致的酶缺乏被认为是日本受试者各种炎性疾病的遗传危险因素。施用重组血浆PAF-AH或转移血浆PAF-AH基因改善了动物模型的病理学。因此，血浆PAF-AH的替代将有效地治疗炎性疾病的患者和新颖的临床方法。此外，