Quantification and Carbon and Nitrogen Isotopic Measurements of Heme B in Environmental Samples
Quantification and Carbon and Nitrogen Isotopic Measurements of Heme B in Environmental Samples
复制标题
环境样品中血红素 B 的定量和碳氮同位素测量
DOI：
10.1021/acs.analchem.0c01711
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发表时间：
2020
影响因子：
7.4
通讯作者：
Naohiko Ohkouchi
中科院分区：
文献类型：
--
作者：
Yuta Isaji;Nanako O. Ogawa;Yoshinori Takano;Naohiko Ohkouchi
血红素B是一种铁配位的四吡咯分子，在血红素蛋白中起辅助因子的作用。asb型血红素蛋白广泛存在于环境中，催化多种必需的生化反应。在这项研究中，我们开发了一种分析方法来量化血红素B在生物和环境样品中使用高效液相色谱法（HPLC）耦合到光电二极管阵列检测器。我们的方法的适用性进一步扩大了使用液相色谱/质谱法（LC/MS;检测限：101 fmol），这使得微量的溶解血红素B在过滤的海水和沉积血红素B与丰富的干扰有机基质共存的定量。对于化合物特定的碳和氮同位素测量，血红素B成功地分离和纯化的生物和环境样品的阴离子交换柱色谱，甲酯化，和双步骤HPLC的组合。光养微生物中血红素B的碳、氮同位素组成与叶绿素相似，而近岸水体和潮间带沉积物中的悬浮颗粒物中血红素B相对于叶绿素而言13 C贫、15 N富，表明非光养微生物也是自然环境中血红素B的重要来源。
Heme B is an iron-coordinated tetrapyrrole molecule that acts as a cofactor in hemoproteins. It is expected to be ubiquitous in the environment, asb-type hemoproteins catalyze a variety of essential biochemical reactions. In this study, we developed an analytical method to quantify heme B in biological and environmental samples using high-performance liquid chromatography (HPLC) coupled to a photodiode array detector. The applicability of our method was further extended by the use of liquid chromatography/mass spectrometry (LC/MS; detection limit: ∼1 fmol), which enabled the quantification of a trace amount of dissolved heme B in filtered seawater and sedimentary heme B coexisting with an abundant interfering organic matrix. For compound-specific carbon and nitrogen isotopic measurements, heme B was successfully isolated and purified from biological and environmental samples by a combination of anion-exchange column chromatography, methyl esterification, and dual-step HPLC. While carbon and nitrogen isotopic compositions of heme B in phototrophs were mostly comparable to those of chlorophylla, heme B in suspended particulate materials in coastal water and an intertidal sediment was13C-depleted and15N-enriched relative to chlorophylla, suggesting that nonphototrophic microorganisms are also a significant source of heme B in natural environments.