a Department of Chemistry, Faculty of Arts and Sciences , Yildiz Technical University , Istanbul , Turkey.
b Department of Bioengineering, Faculty of Chemical and Metallurgical Engineering , Yildiz Technical University , Istanbul , Turkey.
Artif Cells Nanomed Biotechnol. 2018 Jun;46(4):788-794. doi: 10.1080/21691401.2017.1345920. Epub 2017 Jul 6.
In this article, aldehyde derivative of poly(ethylene glycol) (PEG) was synthesized directly with sodium periodate agent. To obtain a conjugate which possesses better stability, PEG aldehyde was bonded to native enzyme with different molar ratios. The conjugation reaction turned out to be efficient and mild. Colorimetric method was applied to evaluate the enzymatic activity of native GOD and its derivatives by introducing another enzyme, horseradish peroxidase. The GOD-PEG aldehyde conjugate with polymeric chains exhibited reduced enzymatic activity towards the catalytical oxidation of glucose, but with significantly increased thermal stability and elongated lifetime. When GOD was modified with PEG aldehyde the enzymatic activity was decreased 40% at 30 °C. However, when incubated at 60 °C the GOD-PEG aldehyde conjugate still retained the enzyme bioactivity of 40% bioactivity left after 4 h, whereas the native GOD lost almost all the activity in 4 h. The polymer chain attached, the more reduction of the enzymatic activity resulted, however, the longer the lifetime and higher thermal stability of the enzyme obtained.
在本文中，通过使用高碘酸钠试剂，将聚乙二醇（PEG）的醛衍生物直接合成。为了获得稳定性更好的缀合物，用不同摩尔比的 PEG 醛将天然酶键合。该缀合反应高效温和。通过引入另一种酶辣根过氧化物酶，应用比色法评估了天然 GOD 及其衍生物的酶活性。具有聚合链的 GOD-PEG 醛缀合物对葡萄糖的催化氧化表现出降低的酶活性，但具有显著提高的热稳定性和延长的半衰期。当 GOD 用 PEG 醛修饰时，在 30°C 时酶活性降低了 40%。然而，当在 60°C 孵育时，GOD-PEG 醛缀合物在 4 小时后仍保留 40%的酶生物活性，而天然 GOD 在 4 小时内几乎失去了所有活性。附着的聚合物链越多，酶活性的降低就越明显，但获得的酶的半衰期和热稳定性就越高。
