Safety-Catch Linker A linker which is cleaved by performing two different reactions instead of the normal single step, thus providing greater control over the timing of compound release.
Scaffold Core portion of a molecule common to all members of a combinatorial library.
Scavenger Resin Solid-supported reagent which will react with undesired materials (such as excess reagents) and remove them from solution.
Serine Protease A family of proteases, characterized by a serine amino acid at its active site.
SELEX "Systematic Evolution of Ligands by Exponential Enrichment". Process for identifying aptamers by iterative enrichment of oligonucleotide mixtures with respect to their ability to bind a target.
Sequestration-Enabling Reagent Reagent which converts undesired by-products or residual starting materials into a form which may more easily be removed from the reaction mixture by, for example, solid phase extraction or other phase switch.
Site Isolation Property of solid supports, whereby functional groups are separated from each other by the polymeric framework, and thus, while they may be physically in close proximity, reduced levels of reaction between sites may be observed. Also referred to as pseudo-dilution.
Solid Phase Extraction Method for sample purification, whereby either the desired or undesired components of a mixture have preferential affinity for a solid material. Adding the mixture to the solid material then allows facile separation of the desired material by filtration.
Solid Support Insoluble, functionalized, polymeric material to which library members or reagents may be attached (often via a linker) allowing them to be readily separated (by filtration, centrifugation, etc.) from excess reagents, soluble reaction by-products or solvents.
Soluble Support An attachment, common to all library members, which renders the library components soluble under conditions for library synthesis, but which can be readily separated from most other soluble components when desired by some simple physical process. This process has been termed liquid phase chemistry. Examples of soluble supports include linear polymers such as poly(ethylene glycol), dendrimers or fuorinated compounds which selectively partition into fluorine-rich solvents.
Sort and Combine Use of directed sorting to facilitate library assembly. Related to pool/split protocol, but more commonly applied to macroscopic solid supports (such as pins and related carriers) where each library member is found on only one, or a small number of carriers.
Spatially Addressable Having the ability to identify at least part of the structure of a library component or pool by noting its physical location in an array.
Spectroscopy Is the analysis of the lines of light emitted from excited atoms as the electrons drop back through their orbitals. These lines give the energy and distances of the electronic orbitals.
Structure - Activity Relationship (SAR) An analysis which defines the relationship between the structure of a molecule and its ability to affect a biological system.
Sub-Library A subset of a combinatorial library physically separated from the rest of the library, generally with one or more fixed building blocks.
Sub-Monomer Synthesis Process resulting in an oligomer in which each monomer residue is formed from two or more building blocks. This approach has been used for peptoid synthesis.