蛋白质酸酶-1 (PP1) 的机理研究,这是一个催化性散乱的酶
Claire McWhirter1, Elizabeth A Lund, Eric A Tanifum
1Centre for Chemical Biology, Department of Chemistry, University of Sheffield, Sheffield, UK S3 7HF.
Journal of the American Chemical Society
|September 19, 2008
概括
蛋白酸酶-1 (PP1) 使用酸性和性残留物进行催化. 它与酸盐和酸盐基质的反应显示出类似的松散过渡状态,与非酶反应不同.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 化学动力学 化学动力学
背景情况:
- 蛋白酸酶-1 (PP1) 是一个关键的酶,参与了脱.
- 了解PP1的催化机制对于阐明细胞信号通路至关重要.
研究的目的:
- 通过使用各种基质,研究蛋白质酸酶-1 (PP1) 的催化机制.
- 描述PP1催化水解反应中涉及的过渡状态.
主要方法:
- 使用了线性自由能量关系 (LFER).
- 使用特定基质测量了动态同位素效应 (KIE).
- 分析了pH值概况以确定催化残留物.
主要成果:
- PP1 呈现出一个钟形的pH值概况,其动力pKa值为6.0和7.2对于4-尼托芬酸盐 (4NPP).
- 甲基单和甲基酸盐的酶化水解显示布伦斯特德β值分别为-0.32和-0.30.
- 对两种基质类型来说,KIE表示松散的过渡状态与部分离开组中和.
结论:
- PP1利用了酸性和性催化剂残留物.
- 酸单和酸甲基酸的PP1催化水解的过渡状态相似且相对松散.
- 这些酶过渡状态与它们各自的非酶化水解途径有很大的不同.
相关概念视频
Protein Kinases and Phosphatases
Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein Kinases and Phosphatases
Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Phosphorylation
The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Allosteric 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,...
Amplifying Signals via Enzymatic Cascade
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
Covalently 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.


