本文關(guān)鍵詞：流動(dòng)注射法探究模擬酶催化過(guò)氧亞硝酸根氧化酪氨酸的動(dòng)力學(xué)特征　出處：《光譜學(xué)與光譜分析》2016年12期 　論文類型：期刊論文

  更多相關(guān)文章： 流動(dòng)注射分析儀 氯化血紅素 血紅蛋白 過(guò)氧亞硝酸根

【摘要】：過(guò)氧亞硝酸根作為生物體內(nèi)高活性自由基,能損傷多種生物大分子進(jìn)而引起一系列重大疾病,對(duì)其含量測(cè)定和反應(yīng)機(jī)制的研究具有重要意義。過(guò)氧亞硝酸根性質(zhì)活潑,反應(yīng)速率快,捕捉其動(dòng)態(tài)過(guò)程十分困難。本文首次利用流動(dòng)注射分析儀探究在不同模擬酶血紅蛋白和氯化血紅素的催化下,過(guò)氧亞硝酸根氧化酪氨酸體系的動(dòng)力學(xué)特征。結(jié)果表明:過(guò)氧亞硝酸根在兩種酶催化下氧化酪氨酸的過(guò)程均遵循MichaelisMenten的動(dòng)力學(xué)規(guī)律;根據(jù)米氏常數(shù)K_m和最大初速率V_(max),推斷其反應(yīng)機(jī)制,經(jīng)模擬酶催化的過(guò)氧亞硝酸根能直接氧化與模擬酶結(jié)合后的酪氨酸快速生成酪氨酸二聚體,未生成·OH和O_2~-·。此外,我們還檢測(cè)了不同溫度、pH下兩種模擬酶催化的速率常數(shù),得到血紅蛋白催化該體系的最適條件為25℃和pH 8.0,速率常數(shù)k_(cat)=1.035×10~6 mol·L~(-1)·s~(-1),氯化血紅素適宜在37℃和pH 9.5的條件下催化該體系,速率常數(shù)k_(cat)=6.842×10~5 mol·L~(-1)·s~(-1);比較動(dòng)力學(xué)參數(shù)K_m~(Hb)(4.46μmol·L~(-1))K_m~(Hemin)(4.90μmol·L~(-1)),V_(max)~Hb(Hb)(0.072ΔI_F/s)V_(max)~(Hemin)(0.026ΔI_F/s),發(fā)現(xiàn)最適條件下血紅蛋白的速率常數(shù)大于氯化血紅素,得到血紅蛋白對(duì)于該體系的催化活性高于氯化血紅素。以上結(jié)果為探究酶催化法測(cè)定過(guò)氧亞硝酸根含量及其反應(yīng)機(jī)理提供動(dòng)力學(xué)參數(shù),對(duì)于防治生物體內(nèi)自由基引起的相關(guān)疾病與診斷新技術(shù)的開(kāi)發(fā)奠定理論基礎(chǔ)。
[Abstract]:As a highly active free radical, peroxynitrite can damage many kinds of biological macromolecules and cause a series of major diseases. It is of great significance to determine the content of peroxynitrite and study its reaction mechanism. It is very difficult to capture its dynamic process. This paper first used flow injection analyzer to explore the catalysis of different mimic enzyme hemoglobin and hemin. Kinetic characteristics of tyrosine oxidation by peroxynitrite. The results show that:. The oxidation of tyrosine by peroxynitrite followed the kinetic law of MichaelisMenten. The reaction mechanism was inferred based on the Michaelis constant Kstack and the maximum initial rate V _ S _ max _ I _ _ _. The peroxynitrite catalyzed by the mimic enzyme can directly oxidize tyrosine to form tyrosine dimer without OH and O _ 2O _ 2- 路. In addition, different temperatures have been detected. The optimum conditions of hemoglobin catalyzed the system were obtained at 25 鈩，

本文編號(hào)：1378232