For faster navigation, this Iframe is preloading the Wikiwand page for 负氧离子洞.

负氧离子洞

维基百科,自由的百科全书

丝氨酸蛋白酶(黑色)的负氧离子洞利用酶主链酰胺(蓝色)的氢键稳定底物(红色)过渡状态上的负电荷积聚。
丝氨酸蛋白酶(黑色)的负氧离子洞利用酶主链酰胺(蓝色)的氢键稳定底物(红色)过渡状态上的负电荷积聚。

负氧离子洞(英语:oxyanion hole)指的是酶的活性部分中能够稳定去质子化的氧或醇盐上的过渡态负电荷[1]的空穴。通常由共轭酰胺骨架或带正电荷的残基组成。

稳定的过渡态可以降低反应所需的活化能,从而促进催化作用[2]。例如,胰凝乳蛋白酶的蛋白酶含有负氧离子洞,以稳定蛋白质水解过程中形成的四面体中间阴离子,并保护底物中带负电的氧气不受水分子的影响[3]

另外,负氧离子孔也可以促进底物的进入与稳定。如果底物没有到达反应位点,负氧离子孔就找不到可供稳定化的目标,从而产生空阻直到底物到位(例如血红蛋白中的BPG)。

催化多步反应的酶可以具有多个负氧离子洞,以稳定反应中的不同过渡态[4]

参考

  1. ^ L, Stryer; JM, Berg; JL, Tymoczko. Biochemistry 5th. San Francisco: W.H. Freeman. 2002 [2019-04-07]. ISBN 978-0-7167-4955-4. (原始内容存档于2014-03-11). 
  2. ^ Simón, Luis; Goodman, Jonathan M. Enzyme Catalysis by Hydrogen Bonds: The Balance between Transition State Binding and Substrate Binding in Oxyanion Holes. doi:10.1021/jo901503d. 
  3. ^ Robert Ménard. Andrew C. Storer. Oxyanion Hole Interactions in Serine and Cysteine Proteases. Biological Chemistry Hoppe-Seyler. 1992, 2: 393–400. doi:10.1515/bchm3.1992.373.2.393. 
  4. ^ Kursula Petri. The Catalytic Cycle of Biosynthetic Thiolase: A Conformational Journey of an Acetyl Group through Four Binding Modes and Two Oxyanion Holes‡ 52 (December 1, 2002). Juha Ojala,Anne-Marie Lambeir,Rik K. Wierenga: 15543–15556. ISSN 0006-2960. doi:10.1021/bi0266232. 
{{bottomLinkPreText}} {{bottomLinkText}}
负氧离子洞
Listen to this article

This browser is not supported by Wikiwand :(
Wikiwand requires a browser with modern capabilities in order to provide you with the best reading experience.
Please download and use one of the following browsers:

This article was just edited, click to reload
This article has been deleted on Wikipedia (Why?)

Back to homepage

Please click Add in the dialog above
Please click Allow in the top-left corner,
then click Install Now in the dialog
Please click Open in the download dialog,
then click Install
Please click the "Downloads" icon in the Safari toolbar, open the first download in the list,
then click Install
{{::$root.activation.text}}

Install Wikiwand

Install on Chrome Install on Firefox
Don't forget to rate us

Tell your friends about Wikiwand!

Gmail Facebook Twitter Link

Enjoying Wikiwand?

Tell your friends and spread the love:
Share on Gmail Share on Facebook Share on Twitter Share on Buffer

Our magic isn't perfect

You can help our automatic cover photo selection by reporting an unsuitable photo.

This photo is visually disturbing This photo is not a good choice

Thank you for helping!


Your input will affect cover photo selection, along with input from other users.