Peroxiredoxin IV is a secretable protein with heparin-binding properties under reduced conditions
Peroxiredoxin IV is a secretable protein with heparin-binding properties under reduced conditions
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DOI：
10.1093/oxfordjournals.jbchem.a022632
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发表时间：
2000-03-01
影响因子：
2.7
通讯作者：
Taniguchi, N
中科院分区：
文献类型：
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作者：
Okado-Matsumoto, A;Matsumoto, A;Taniguchi, N
过氧化还蛋白(PRxs)具有保护无蛋白硫醇基团免受氧化损伤和硫氧还蛋白依赖的过氧化物酶活性的作用。本文描述了哺乳动物Prx的第四个成员Prx IV的特征。通过杆状病毒表达系统在Sf21细胞中产生的大鼠Prx TV有两条不同电泳率的条带，分别为31和27 kDa[MatSumoto等，(1999)Fees Lett，443,246-250]，27 kDa的Prx IV缺少NH2末端的36个氨基酸，与预测的前导肽相对应，这是细胞分泌所必需的。因此，31 kDa的形式可能是前体形式，而27 kDa的形式可能是一种具有酶活性的分泌形式。脉冲追逐实验表明，PRX IV在10分钟内被处理，并从细胞中释放出来。分泌型包括还原和氧化两种形式。还原形式与肝素亲和柱和人脐静脉内皮细胞结合，而氧化形式不结合。表面等离子体共振实验测得肝素和硫酸肝素的平衡离解常数K-D分别为19和870 nm。免疫印迹分析表明，这种分泌形式与大多数组织中发现的主要条带相对应。在细胞内，分泌形式主要定位于内质网，通过与钙网蛋白的共同定位来判断。此外，PRX IV除了硫氧还蛋白依赖的活性外，还具有谷胱甘肽依赖的过氧化物酶活性。这些数据表明，Prx IV是一种可分泌的蛋白质，可能通过清除细胞外间隙中的活性氧来发挥其对氧化损伤的保护作用。
Peroxiredoxins (PRxs) play a role in protecting protein free thiol groups against oxidative damage and thioredoxin-dependent peroxidase activity. This report describes the characteristics of the fourth member of the mammalian PRxs, PRx IV. Rat PRx TV produced in Sf21 cells by a baculovirus expression system has two bands with different electrophoretic mobilities, 31 and 27 kDa [Matsumoto et al, (1999) FEES Lett, 443, 246-250], The 27-kDa PRx IV lacks the NH2-terminal 36 amino acids which correspond to a predicted leader peptide, which is required for secretion from cells. Thus, the 31-kDa form is probably a precursor form, and the 27-kDa form, a secretable form which is enzymatically active. Pulse-chase experiments of PRx IV-transfected COS-1 cells showed that PRx IV is processed within 10 min and released from cells. The secretable form contains both reduced and oxidized forms. The reduced form binds to both a heparin affinity column and human umbilical vein endothelial cells, while the oxidized form does not. The equilibrium dissociation constants, K-D, for heparin and heparan sulfate as judged by surface plasmon resonance experiments were 19 and 870 nM, respectively. The secretable form corresponds to the major bands found in most tissues, as evidenced by immunoblot analysis. Within cells, secretable form was largely localized on the endoplasmic reticulum, as judged by colocalization with calreticulin. Moreover, PRx IV has glutathione-dependent peroxidase activity in addition to thioredoxin-dependent activity. These data indicate that PRx IV is a secretable protein and may exert its protective function against oxidative damage by scavenging reactive oxygen species in the extracellular space.