Dalton
Dalton — A unit of molecular mass equal to one-twelfth the mass of a carbon-12 atom (approximately 1.66 × 10â»Â²â´ grams). Used to express peptide molecular weight.
What Is a Dalton?
A dalton (Da) is the unit of molecular weight equal to 1/12 the mass of a carbon-12 atom (1.66 x 10⁻²⁴ g). Peptide molecular weights are expressed in daltons (Da) or kilodaltons (kDa). The average amino acid residue weighs ~111 Da, so a 15-residue peptide like BPC-157 is ~1,419 Da.
Context
- Peptides: 200-5,000 Da (2-50 residues). Most research peptides are 500-3,000 Da
- MS measurement: Monoisotopic mass (most abundant isotope) vs. average mass
- Drug classification: < 500 Da = small molecule. 500-5,000 Da = peptide. > 5,000 Da = protein/biologic
Frequently Asked Questions
What is Dalton?
A unit of molecular mass equal to one-twelfth the mass of a carbon-12 atom (approximately 1.66 × 10â»Â²â´ grams). Used to express peptide molecular weight.
Why is Dalton important in peptide research?
Dalton is a fundamental concept in unit as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.