銅 (II) -ペロクソ種によって誘発されたチロシナーゼにおける翻訳後のHis-Cysクロスリンク形成
Nobutaka Fujieda1, Takuya Ikeda, Michiaki Murata
1Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Journal of the American Chemical Society
|January 12, 2011
まとめ
タイロシナーゼ (Aspergillus oryzae) のHis-Cysクロスリンクの自己触媒的形成は,アポ酵素が銅で処理されたときに発生します. この反応において,二銅 (II) 酸化過酸化物の中間物質が決定的であると提案されている.
科学分野:
- バイオケミストリー バイオケミストリー
- 酵素学 酵素学とは
- メタロプロテイン化学
背景:
- タイロシナゼは,メラニンの生物合成に不可欠な銅を含む酵素です.
- タイロシナーゼの触媒メカニズムを理解することは,様々なバイオテクノロジーの応用に不可欠です.
研究 の 目的:
- Aspergillus oryzaeチロシナゼにおけるオートカタリティックなHis-Cysクロスリンク形成のメカニズムを解明する.
- 酵素の活性化プロセスに関与する主要な反応性中間物質を特定する.
主な方法:
- チロシナゼアポエンザイムをエアロビック条件下でCu (II) で処理する.
- 反応中間物質の特徴を特定するために,光譜および運動分析を行います.
主要な成果:
- タイロシナーゼ活性部位におけるHis-Cysクロスリンクの自己触媒的形成の実証.
- 重要な中間物質として (μ-η(2):η(2)-peroxo) dicopper(II) 種の関与を示唆する証拠がある.
結論:
- この研究は,チロシナーゼにおけるHis-Cysクロスリンクの新たな自己触媒機構を明らかにした.
- 提案された二銅 (II) 酸化過酸化物中間体は,金属酵素における銅と酸素の活性化に関する洞察を提供します.
![[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
関連する概念動画
01:26Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
01:24Peroxisomes
Peroxisomes are specialized organelles present in fungi, plant, and animal cells. It can vary in number, size, morphology, and activity depending on the type of tissue and the nutritional state of the cell. For example, cells with active lipid metabolism, such as adipocytes, neurons, and hepatocytes, have more peroxisomes than other cells in the body. Besides their primary role in breaking down complex organic molecules, peroxisomes can also synthesize specific macromolecules and participate in...
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
01:20Radical Autoxidation
The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...