Related Experiment Video
Updated: Feb 11, 2026
05:57
Author Spotlight: In Silico Creation and Impact of Carbonylated Amino Acids on Protein Structure and Function
Published on: April 26, 2024
887
Caldesmon, acidic amino acids and molecular weight determinations
1Baylor College of Medicine, Houston, Texas 77030.
Journal of Muscle Research and Cell Motility
|April 1, 1989
Summary
Smooth muscle caldesmons are smaller than previously believed, with their unusual behavior in SDS-PAGE linked to high acidic amino acid content. This finding necessitates re-evaluating caldesmon
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Biology
Background:
- Smooth muscle caldesmons are proteins involved in muscle contraction.
- Previous studies estimated larger molecular weights for caldesmons.
- The interaction of caldesmon with other thin filament proteins is not fully understood.
Purpose of the Study:
- To determine the accurate molecular weight of smooth muscle caldesmons.
- To investigate the reasons for anomalous protein behavior during electrophoresis.
- To re-evaluate the stoichiometry and interactions of caldesmon within the thin filament.
Main Methods:
- Estimates of molecular weight using advanced techniques.
- Complementary DNA (cDNA) sequencing.
- Analysis of protein behavior during SDS-polyacrylamide gel electrophoresis (SDS-PAGE).
Main Results:
- Recent estimates indicate smooth muscle caldesmons are significantly smaller than previously thought.
- The anomalous migration of caldesmons in SDS-PAGE correlates with their high content of acidic amino acids.
- These findings challenge existing models of caldesmon function.
Conclusions:
- The molecular weight of smooth muscle caldesmons needs revision.
- High acidic amino acid content explains caldesmon's electrophoretic behavior.
- Stoichiometric ratios of caldesmon to tropomyosin and actin, and its interaction with calmodulin, require re-evaluation.
Related Concept Videos
01:29Amino Acid Biosynthetic Pathways
1.3K
Amino acid biosynthesis is essential for cell growth, protein synthesis, and metabolic regulation. Cells generate essential and non-essential amino acids from metabolic intermediates to sustain vital biological functions. These intermediates originate from key metabolic pathways: glycolysis, the tricarboxylic acid (TCA) cycle, and the pentose phosphate pathway. Important precursors include α-ketoglutarate, pyruvate, oxaloacetate, phosphoenolpyruvate, and erythrose-4-phosphate, which...
1.3K
01:18Amino Acid Catabolism
1.2K
Microorganisms rely on proteins as an essential carbon and energy source, particularly in environments with limited polysaccharides or lipids. However, proteins are too large to cross the plasma membrane unaided, necessitating enzymatic degradation. Microbes secrete extracellular proteases and peptidases that hydrolyze proteins into peptides, which can then be transported across the membrane. Once inside the cell, intracellular proteases degrade these peptides into free amino acids, which...
1.2K
03:42Amino acids
106.2K
Amino acids are the monomers that comprise proteins. Each amino acid has the same fundamental structure, which consists of a central carbon atom, or the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom. Every amino acid also has another atom or group of atoms bonded to the central atom known as the R group. There are 20 common amino acids present in proteins, each with a different R group. Variation in the amino acid sequence is responsible for...
106.2K
03:05Acid Strength and Molecular Structure
33.2K
Binary Acids and Bases
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
33.2K
02:34Molecular Structure and Acidity
21.6K
An acid can be deprotonated to form a conjugate base or an anion. If the produced anion is more stable, then the acid is stronger. On the contrary, if the anion is unstable, then the acid is weaker. Hence, to determine the acidity of the compound, the stability of its conjugate base is studied using various factors.
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
21.6K
03:27Mixtures of Acids
21.9K
The pH of a solution containing an acid can be determined using its acid dissociation constant and its initial concentration. If a solution contains two different acids, then its pH can be determined using one of several methods depending upon the relative strength of the acids and their dissociation constants.
A Mixture of a Strong Acid and a Weak Acid
In a mixture of a strong acid and a weak acid, the strong acid dissociates completely and becomes a source of almost all the hydronium ions...
A Mixture of a Strong Acid and a Weak Acid
In a mixture of a strong acid and a weak acid, the strong acid dissociates completely and becomes a source of almost all the hydronium ions...
21.9K