Table of Contents
- 1 What is the difference between molecular weight and size?
- 2 What is protein size?
- 3 Are all proteins the same size?
- 4 Why is protein size important?
- 5 What is the difference between gram molecular weight and molecular weight?
- 6 How do you calculate the molecular weight of a protein?
- 7 Why do proteins have more than one sequence variant?
What is the difference between molecular weight and size?
Whereas molecular weight is the mass of a molecule of a particular substance. While the definition and units are different for molar mass and molecular weight, the value is the same….Difference Between Molar Mass and Molecular Weight.
| Basis | Molar Mass | Molecular Weight |
|---|---|---|
| Unit | Kgmol-1 | Atomic mass units |
What is protein size?
The size of a synthesized protein can be measured by the number of amino acids it contains and by its total molecular mass, which is normally reported in units of daltons (synonymous with atomic mass units), or the derivative unit kilodalton (kDa).
What is the molecular size of a protein?
A simple rule of thumb for thinking about typical soluble proteins like the Rubisco monomer is that they are 3-6 nm in diameter as illustrated in Figure 1 which shows not only Rubisco, but many other important proteins that make cells work.
What is molecular weight of protein?
The molecular weights of a large number of proteins have been determined. Most consist of several subunits, the molecular weight of which is usually less than 100,000 and frequently ranges from 20,000 to 30,000.
Are all proteins the same size?
Proteins come in a wide variety of shapes, and they are generally between 50 and 2000 amino acids long. Large proteins generally consist of several distinct protein domains—structural units that fold more or less independently of each other, as we discuss below.
Why is protein size important?
The size of a protein is an important physical characteristic that provides useful information including the presence of monomers, dimer and trimer, changes in conformation, aggregation state, and denaturation.
How can any difference between the molecular weight of the protein and its predicted molecular weight be explained?
The size of the protein can be determined through separation by electrophoresis – smaller proteins migrate faster than their larger counterparts. The calculated (or predicted) molecular weight of a protein is determined by adding the actual molecular weights of individual amino acids in a given protein.
Why is molecular weight important for protein?
As the primary structure is the most foundational level of protein structure, protein molecular weight is a key parameter to confirm. Having a robust understanding of the unmodified protein molecular weight can help in initial assessments of the biomolecule’s functionality. This could include: Metabolic regulation.
What is the difference between gram molecular weight and molecular weight?
It can also be expressed as kilogram per mole. Molecular mass is expressed in atomic mass units….Molar mass:
| Difference between Molar mass and Molecular mass | |
|---|---|
| Example: Mass of 1 mole of oxygen is 15.9994 grams. Therefore, the molar mass = 15.9994 g/mol | Example: Molecular mass of Ca(OH)2 = 74 atomic mass units |
How do you calculate the molecular weight of a protein?
The molecular weight of a protein is the weight of 1 mole or N (Avogadro’s number) number of molecules of the protein. Its unit is generally Dalton or kiloDalton.
Why is the molecular weight of a non-chemically modified protein larger than predicted?
[…] The molecular weight (MW) of a protein can be predicted based on its amino acids (AA) composition. However, in many cases a non-chemically modified protein shows an SDS PAGE-displayed MW larger than its predicted size. Some reports linked this fact to high content of acidic AA in the protein.
What is the difference between Daltons and molecular weight?
The definition of a Dalton is the Dalton (or atomic mass unit (amu) ) is a unit of mass defined as 1/12 weight of carbon-12 atom in ground state. So, to convert Daltons to molecular weight in g/mol, multiply by one. In other words, they are the same.
Why do proteins have more than one sequence variant?
Many proteins encoded by a single gene exist in more than one sequence variant, or protein isoform, due to alternative splicing during mRNA maturation. This can result in additional protein-coding sequences and higher molecular weight protein products, or proteins of lower molecular weight owing to premature stop codons.