Unraveling the complexity of circulating forms of brain natriuretic peptide.
Unraveling the complexity of circulating forms of brain natriuretic peptide.
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DOI：
10.1373/clinchem.2007.086611
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发表时间：
2007-07
影响因子：
9.3
通讯作者：
Rebekah L. Gundry;J. V. Van Eyk
中科院分区：
文献类型：
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作者：
Rebekah L. Gundry;J. V. Van Eyk
确定生物标志物的循环形式对于开发高灵敏度和特异性的免疫测定至关重要。脑利钠肽（BNP）激素在心房中作为激素前体产生，其信号序列的切割产生循环激素前体proBNP（氨基酸残基1-108，人序列）。激素原随后被切割，产生76个氨基酸的n端（NT）片段（NT-proBNP）和33个氨基酸的活性激素BNP（由proBNP残基77-108组成）。这两种市售免疫检测方法可检测循环NT片段或BNP，并可能检测proBNP。然而，这些检测是否检测到所有可能的循环形式的BNP仍不清楚。BNP的潜在循环形式具有不同的内在物理特性，这些特性可以决定抗原性、分离过程中的非特异性结合程度、内源性清除动力学、循环半衰期和/或对其他蛋白质的亲和力，包括细胞受体和假定的血清/血浆载体蛋白。因此，表征每种循环形式的BNP的物理状态是检测发展的关键。确定循环BNP形式是否具有翻译后修饰（PTM），如磷酸化或N-和o -链糖基化，和/或与其他蛋白质结合是至关重要的。在最近一期的《临床化学》上，Seferian等人(1)的一篇文章描述了两种阐明BNP循环形式的方法。这两种策略检查了(a)抗原性，(b)抗体结合，以及(c)未经修饰的重组形式和循环内源性形式的理论和观察到的分子量的差异。数据表明，循环BNP的化学性质是复杂的。这种复杂性需要在免疫分析开发过程中加以考虑。有潜在的PTM吗？Seferian等人(1)产生了大量的肽和BNP片段（pro、NT-pro和BNP）……
Determining the circulating form of a biomarker is critical for the development of a highly sensitive and specific immunoassay. The hormone brain natriuretic peptide (BNP) is produced in the atria as a preprohormone, and the cleavage of its signal sequence produces the circulating prohormone proBNP (amino acid residues 1–108, human sequence). The prohormone is subsequently cut to yield a 76-amino acid N-terminal (NT) fragment (NT-proBNP) and the 33-amino acid active hormone BNP (comprising residues 77–108 of proBNP). The 2 commercially available immunoassays detect either the circulating NT fragment or BNP and, potentially, could detect proBNP. However, whether these assays detect all possible circulating forms of BNP remains unclear. The potential circulating forms of BNP have different intrinsic physical characteristics that can dictate antigenicity, extent of nonspecific binding during isolation, endogenous clearance kinetics, circulating half-life, and/or affinity for other proteins including cellular receptors and putative serum/plasma carrier proteins. Consequently, characterization of the physical status of each circulating form of BNP is key to assay development. It is critical to determine whether the circulating BNP forms have posttranslational modifications (PTM), such as phosphorylation or N- and O-linked glycosylation, and/or bind to other protein(s). In a recent issue of Clinical Chemistry , an article by Seferian et al. (1) described 2 approaches to shedding light on the circulating forms of BNP. The 2 strategies examined differences in ( a ) antigenicity, ( b ) antibody binding, and ( c ) the theoretical and observed MWs of the unmodified recombinant form and the circulating endogenous form(s). The data presented indicated that the chemistry of circulating BNP is complex. This complexity needs to be taken into account during immunoassay development. Is there a potential PTM? Seferian et al. (1) produced a large number of peptides and fragments of BNP (pro, NT-pro, and BNP) …