Related Experiment Video
Updated: Jul 8, 2025
10:28
A Semi-High-Throughput Adaptation of the NADH-Coupled ATPase Assay for Screening Small Molecule Inhibitors
Published on: August 17, 2019
9.6K
Does muscle-type myosin have ADPase activity?
Ilya G Vyatchin1, Ulyana V Shevchenko1, Vyacheslav A Dyachuk1
1Laboratory of Cell Biophysics, A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Ul. Palchevskogo 17, Vladivostok, 690041, Russia.
Biochemical and Biophysical Research Communications
|December 14, 2023
Summary
Adenosine diphosphate (ADP) acts as a myosin substrate in muscle contraction, challenging its traditional role as merely a byproduct. This finding reveals new insights into muscle energy dynamics and myosin interactions.
Area of Science:
- Muscle physiology
- Biochemistry
- Molecular biology
Background:
- Adenosine diphosphate (ADP) is typically viewed as a byproduct of myosin cross-bridge cycling during muscle contraction.
- Its role beyond being a final product has been largely overlooked in muscle studies.
Purpose of the Study:
- To investigate the potential role of ADP as a substrate for myosins.
- To challenge the conventional understanding of ADP's function in muscle contraction.
Main Methods:
- Biophysical techniques
- Biochemical assays
Main Results:
- ADP was demonstrated to function as a substrate for myosins in smooth and striated adductor muscles of bivalves and vertebrate skeletal muscles.
- Observed differences between ATP and ADP effects on actomyosin properties were quantitative.
- High concentrations ( > 0.3 mM) of both ATP and ADP can depolymerize polymeric myosin, explaining prior inhibitory observations.
Conclusions:
- ADP can actively participate as a substrate in muscle contraction, not just a byproduct.
- This redefines the understanding of energy utilization and myosin function in various muscle types.
- Myosin's interaction with nucleotides is more nuanced than previously thought.
Related Concept Videos
01:34ATP Driven Pumps II: P-type Pumps
4.9K
The P-type pumps are a large family of integral membrane transporter ATPases. They are divided into five major types based on substrate specificity, from I to V.
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
4.9K
01:16Actin and Myosin in Muscle Contraction
11.5K
Actin and myosin are contractile proteins that form the sarcomere found in skeletal muscle tissues for regulating muscle contraction. Actin, a globular contractile protein, interacts with myosin for muscle contraction. The skeletal tissue appears striped or striated under a microscope due to the repeated arrangement of contractile proteins actin and myosin along the length of myofibrils. Dark A bands and light I bands repeat along myofibrils, and the alignment of myofibrils in the cell causes...
11.5K
01:18ATP Synthase: Structure
12.5K
ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in response to the electrochemical gradient, producing ATP from ADP and inorganic phosphate. ATP synthase can also work in a reverse direction by hydrolyzing ATP and generating an electrochemical gradient. Different forms of ATP synthases have evolved special features to meet the specific demands of the cell. Based on their specific feature, ATP...
12.5K
01:15Overview of Myosin Structure and Function
4.4K
Myosins are a family of molecular motor proteins, first identified in the skeletal muscles, where they are responsible for muscle contraction. Along with their role in muscle contraction, these proteins also play a role in the intracellular transport of molecules and vesicles. There are twenty-four classes of myosins based on their domain sequence and organization. Of the twenty-four, six classes (Myosin I, Myosin II, Myosin V, Myosin VI, Myosin VII, and Myosin X) have been well...
4.4K
01:25Energy Supply for Muscle Contraction
3.2K
Skeletal muscle fibers have the unique ability to switch between rest and contraction states, using different sources of ATP for energy. The contraction cycle and Ca2+ transport back into the sarcoplasmic reticulum for relaxation require significant ATP. However, the ATP reserves in muscle fibers are limited and can only sustain contractions for a few seconds. Additional ATP production becomes necessary for prolonged contractions. As a result, muscle fibers generate ATP through various sources,...
3.2K
01:48ATP Synthase: Mechanism
14.6K
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased...
14.6K