首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Formation of circular polyribosomes in wheat germ cell-free protein synthesis system
Authors:Madin Kairat  Sawasaki Tatsuya  Kamura Nami  Takai Kazuyuki  Ogasawara Tomio  Yazaki Kazumori  Takei Toshiaki  Miura Kin-Ichiro  Endo Yaeta
Institution:Department of Biomedicine, Division for Anatomy and Cell Biology, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway.
Abstract:We have compared the urea stability of the human aromatic amino acid hydroxylases (AAAHs), key enzymes involved in neurotransmitter biosynthesis and amino acid homeostasis. Tyrosine-, tryptophan- and phenylalanine hydroxylase (TH, TPH and PAH, respectively) were transiently activated at low urea concentrations and rapidly inactivated in >3 M urea. The denaturation of TH occurred through two cooperative transitions, with denaturation midpoints of 1.41+/-0.06 and 5.13+/-0.05 M urea, respectively. Partially denatured human TH (hTH) retained more of its secondary structure than human PAH (hPAH), and was found to exist as tetramers, whereas hPAH dissociated into dimers. Furthermore, the urea-induced aggregation of hPAH was 100-fold higher than for hTH. These results suggest that the denatured state properties of the AAAHs contribute significantly to the stability of these enzymes and their tolerance towards missense mutations.
Keywords:
本文献已被 PubMed 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号