Yield
Definition
How much purified peptide a synthesis produced, as a percentage of the theoretical maximum. Low yield raises cost per milligram and tends to travel with a harder purification, which is why long or difficult sequences are expensive.
Where this term comes up
Entries whose definition mentions Yield.
What this means for research sourcing
Structure and identity terms are what a certificate of analysis is written in. Every Volta compound ships with its sequence, molecular weight and measured purity, so these terms map directly onto the specification on the product page.
Related Terms in Chemistry & Structure
Molecular Weight
The mass of one molecule, in daltons or g/mol. For a peptide it follows arithmetically from the sequence, so a stated weight that does not match the stated sequence is a contradiction on the page and a reason to look harder at the rest of the document.
Kilodalton (kDa)
One thousand daltons, the unit used once a molecule is large enough that daltons become unwieldy. Short peptides are quoted in daltons; proteins and fusion constructs in kDa.
Isoelectric Point (pI)
The pH at which a peptide carries no net charge. Solubility is usually at its worst there, so a material that will not dissolve in a neutral buffer often dissolves once the pH is moved away from its pI.
Zwitterion
A molecule carrying a positive and a negative charge at the same time while being neutral overall. Free amino acids exist as zwitterions at physiological pH, which is why they are far more water-soluble than their structures suggest.
Hydrophilic and Hydrophobic
Whether a region of a molecule associates with water or avoids it. The balance across a sequence sets solubility, how a peptide behaves on a reversed-phase column, and how readily it crosses a lipid membrane.
Solubility
How much of a peptide a given solvent will take into solution. It is sequence-specific rather than general: some materials need a trace of acid or a small percentage of organic solvent before water will carry them, and forcing the issue with agitation causes aggregation instead.
Denaturation
Loss of folded structure through heat, extreme pH or mechanical shear, without the backbone necessarily being cut. The mass can be unchanged while the activity is gone, which is why an identity test alone does not establish that a material is intact.
Counter-Ion
The small ion supplied alongside a charged peptide to balance it, usually acetate and sometimes trifluoroacetate. It is part of the powder's mass, so gross vial weight and peptide content are two different numbers.