Sarkissian Christineh N, Gámez Alejandra, Wang Lin, Charbonneau Marilyse, Fitzpatrick Paul, Lemontt Jeffrey F, Zhao Bin, Vellard Michael, Bell Sean M, Henschell Carroll, Lambert Amy, Tsuruda Laurie, Stevens Raymond C, Scriver Charles R
Department of Biology, McGill University, Montreal, QC, Canada H3A 1B1.
Proc Natl Acad Sci U S A. 2008 Dec 30;105(52):20894-9. doi: 10.1073/pnas.0808421105. Epub 2008 Dec 18.
Phenylketonuria (PKU) is a metabolic disorder, in which loss of phenylalanine hydroxylase activity results in neurotoxic levels of phenylalanine. We used the Pah(enu2/enu2) PKU mouse model in short- and long-term studies of enzyme substitution therapy with PEGylated phenylalanine ammonia lyase (PEG-PAL conjugates) from 4 different species. The most therapeutically effective PAL (Av, Anabaena variabilis) species was one without the highest specific activity, but with the highest stability; indicating the importance of protein stability in the development of effective protein therapeutics. A PEG-Av-p.C503S/p.C565S-PAL effectively lowered phenylalanine levels in both vascular space and brain tissue over a >90 day trial period, resulting in reduced manifestations associated with PKU, including reversal of PKU-associated hypopigmentation and enhanced animal health. Phenylalanine reduction occurred in a dose- and loading-dependent manner, and PEGylation reduced the neutralizing immune response to the enzyme. Human clinical trials with PEG-Av-p.C503S/p.C565S-PAL as a treatment for PKU are underway.
苯丙酮尿症（PKU）是一种代谢紊乱疾病，其中苯丙氨酸羟化酶活性丧失导致苯丙氨酸达到神经毒性水平。我们使用Pah(enu2/enu2) PKU小鼠模型，对来自4个不同物种的聚乙二醇化苯丙氨酸解氨酶（PEG-PAL缀合物）进行酶替代疗法的短期和长期研究。治疗效果最佳的PAL（Av，可变鱼腥藻）物种并非比活性最高的物种，而是稳定性最高的物种；这表明蛋白质稳定性在有效蛋白质治疗药物开发中的重要性。在超过90天的试验期内，一种PEG-Av-p.C503S/p.C565S-PAL有效降低了血管间隙和脑组织中的苯丙氨酸水平，减少了与PKU相关的表现，包括PKU相关色素减退的逆转和动物健康状况的改善。苯丙氨酸的降低呈剂量和负荷依赖性，聚乙二醇化减少了对该酶的中和免疫反应。以PEG-Av-p.C503S/p.C565S-PAL作为PKU治疗方法的人体临床试验正在进行中。
