Kaiser Test
Definition
A colour test using ninhydrin that detects free primary amines on resin beads, used to confirm a coupling went to completion. A blue result means unreacted amine remains and the coupling should be repeated.
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
Trityl (Trt)
A bulky acid-labile protecting group used on cysteine, histidine, asparagine and glutamine side chains. Its sensitivity to mild acid is what makes selective removal possible while other groups stay in place.
Acetamidomethyl (Acm)
A cysteine protecting group that survives the acid used for final cleavage. Leaving it on lets disulfide bridges be formed deliberately and in a chosen order rather than at random.
Dimerisation
Two molecules associating or bonding into one unit. For peptides it most often means an unintended disulfide-linked dimer, which appears as a distinct peak at twice the expected mass.
Hydrophilicity
Affinity for water. In peptides it is set by the balance of polar and charged residues, and together with its opposite it governs solubility, how the chain folds, and where it elutes in reversed-phase chromatography.
Lipophilicity
Affinity for fats and non-polar solvents, usually quantified as a partition coefficient. Acylation raises it deliberately, which is how several long-acting analogues achieve albumin binding.
Quaternary Structure
The arrangement of two or more folded chains into one functional assembly. It is the level above tertiary structure and applies only to multi-subunit molecules, which most research peptides are not.
Protein Folding
The process by which a chain adopts its three-dimensional shape, driven mainly by burying hydrophobic residues away from water. Activity usually depends on the fold, which is why a denatured molecule can be chemically intact and inert.
Glycosylation
Attachment of sugar chains to a protein, typically at asparagine or at serine and threonine. It affects stability, solubility and clearance, and it is a reason a recombinant molecule may differ from the same sequence made synthetically.