氧化壓力、蠶豆症與生物功能

Oxidative Stress, Favism and Biologic Function

葡萄糖六磷酸脫氫酶（G6PD）經由產生細胞裡最重要的還原劑NADPH保護細胞不受高氧化壓力所引發的氧化損傷是知之已久的事實，所以傳統的認知把G6PD定位為抗氧化酵素。新的知識指出NADPH不但是抗氧化劑，同時亦可經由NADPH oxidase或nitric oxide synthase此兩酵素產生O2或NO此等活性氧分子，所以NADPH也同時被定位為助氧化劑，而由此產生的活性氧分子在細胞內扮演極重要的信號傳遞角色去推動許多細胞功能。G6PD可經由調控NADPH在細胞內的流量達到調控許多細胞運作之角色，本文將呈現G6PD的去毒物、抗病毒及胚胎發育等新角色。

Glucose-6-phosphate dehydrogenase (G6PD) has long been known as an important antioxidative enzyme by regenerating NADPH to protect cells from high oxidative stress which can lead to oxidative damage. Besides its well-known antioxidant role, NADPH is now recognized that it can also serve as pro-oxidant by way of NADPH oxidase (NOX) and nitric oxide synthase (NOS) to produce superoxide and nitric oxide respectively. These reactive species are important in maintaining redox homeostasis and participating in signal transduction for many cellular processes. Hence, by modulating the flow of NADPH, G6PD can have a proper control of many cellular processes. In this article, evidence for G6PD to play new roles in such processes as detoxication of xenobiotics, antiviral function, and embryogenesis will be reviewed.