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Ferric heme b in aqueous micellar and vesicular systems: state-of-the-art and challenges
- Nemanja Cvjetan, Peter Walde
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- Journal:
- Quarterly Reviews of Biophysics / Volume 56 / 2023
- Published online by Cambridge University Press:
- 11 January 2023, e1
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- Article
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Ferric heme b (= ferric protoporphyrin IX = hemin) is an important prosthetic group of different types of enzymes, including the intensively investigated and widely applied horseradish peroxidase (HRP). In HRP, hemin is present in monomeric form in a hydrophobic pocket containing among other amino acid side chains the two imidazoyl groups of His170 and His42. Both amino acids are important for the peroxidase activity of HRP as an axial ligand of hemin (proximal His170) and as an acid/base catalyst (distal His42). A key feature of the peroxidase mechanism of HRP is the initial formation of compound I under heterolytic cleavage of added hydrogen peroxide as a terminal oxidant. Investigations of free hemin dispersed in aqueous solution showed that different types of hemin dimers can form, depending on the experimental conditions, possibly resulting in hemin crystallization. Although it has been recognized already in the 1970s that hemin aggregation can be prevented in aqueous solution by using micelle-forming amphiphiles, it remains a challenge to prepare hemin-containing micellar and vesicular systems with peroxidase-like activities. Such systems are of interest as cheap HRP-mimicking catalysts for analytical and synthetic applications. Some of the key concepts on which research in this fascinating and interdisciplinary field is based are summarized, along with major accomplishments and possible directions for further improvement. A systematic analysis of the physico-chemical properties of hemin in aqueous micellar solutions and vesicular dispersions must be combined with a reliable evaluation of its catalytic activity. Future studies should show how well the molecular complexity around hemin in HRP can be mimicked by using micelles or vesicles. Because of the importance of heme b in virtually all biological systems and the fact that porphyrins and hemes can be obtained under potentially prebiotic conditions, ideas exist about the possible role of heme-containing micellar and vesicular systems in prebiotic times.
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- By Kumar Alagappan, Janet G. Alteveer, Kim Askew, Paul S. Auerbach, Katherine Bakes, Kip Benko, Paul D. Biddinger, Victoria Brazil, Anthony FT Brown, Andrew K. Chang, Alice Chiao, Wendy C. Coates, Jamie Collings, Gilbert Abou Dagher, Jonathan E. Davis, Peter DeBlieux, Alessandro Dellai, Emily Doelger, Pamela L. Dyne, Gino Farina, Robert Galli, Gus M. Garmel, Daniel Garza, Laleh Gharahbaghian, Gregory H. Gilbert, Michael A. Gisondi, Steven Go, Jeffrey M. Goodloe, Swaminatha V. Gurudevan, Micelle J. Haydel, Stephen R. Hayden, Corey R. Heitz, Gregory W. Hendey, Mel Herbert, Cherri Hobgood, Michelle Huston, Loretta Jackson-Williams, Anja K. Jaehne, Mary Beth Johnson, H. Brendan Kelleher, Peter G Kumasaka, Melissa J. Lamberson, Mary Lanctot-Herbert, Erik Laurin, Brian Lin, Michelle Lin, Douglas Lowery-North, Sharon E. Mace, S. V. Mahadevan, Thomas M. Mailhot, Diku Mandavia, David E. Manthey, Jorge A. Martinez, Amal Mattu, Lynne McCullough, Steve McLaughlin, Timothy Meyers, Gregory J. Moran, Randall T. Myers, Christopher R.H. Newton, Flavia Nobay, Robert L. Norris, Catherine Oliver, Jennifer A. Oman, Rita Oregon, Phillips Perera, Susan B. Promes, Emanuel P. Rivers, John S. Rose, Carolyn J. Sachs, Jairo I. Santanilla, Rawle A. Seupaul, Fred A. Severyn, Ghazala Q. Sharieff, Lee W. Shockley, Stefanie Simmons, Barry C. Simon, Shannon Sovndal, George Sternbach, Matthew Strehlow, Eustacia (Jo) Su, Stuart P. Swadron, Jeffrey A. Tabas, Sophie Terp, R. Jason Thurman, David A. Wald, Sarah R. Williams, Teresa S. Wu, Ken Zafren
- Edited by S. V. Mahadevan, Stanford University School of Medicine, California, Gus M. Garmel
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- Book:
- An Introduction to Clinical Emergency Medicine
- Published online:
- 05 May 2012
- Print publication:
- 10 April 2012, pp xi-xvi
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