Editing Biotin (section)

==Use in biotechnology==
Chemically modified versions of biotin are widely used throughout the [[biotechnology]] industry to isolate proteins and non-protein compounds for biochemical [[assay]]s.<ref name=ThermoFisher>{{cite web |url=http://www.piercenet.com/browse.cfm?fldID=4DDCADD2-5056-8A76-4E7E-2E00843BE346 |title=Overview of Protein Labeling |publisher=[[Thermo Fisher Scientific]] |access-date=22 April 2012 |archive-date=September 26, 2012 |archive-url=https://web.archive.org/web/20120926034604/http://www.piercenet.com/browse.cfm?fldID=4DDCADD2-5056-8A76-4E7E-2E00843BE346 |url-status=live }}</ref> Because egg-derived [[avidin]] binds strongly to biotin with a [[dissociation constant]] ''K''<sub>d</sub> ≈ 10<sup>−15</sup>&nbsp;M,<ref name=Laitinen2006>{{cite journal | vauthors = Laitinen OH, Hytönen VP, Nordlund HR, Kulomaa MS | s2cid = 7180383 | title = Genetically engineered avidins and streptavidins | journal = Cellular and Molecular Life Sciences | volume = 63 | issue = 24 | pages = 2992–3017 | date = December 2006 | pmid = 17086379 | doi = 10.1007/s00018-006-6288-z | pmc = 11136427 }}</ref> biotinylated compounds of interest can be isolated from a sample by exploiting this highly stable interaction. First, the chemically modified biotin reagents are bound to the targeted compounds in a solution via a process called biotinylation. The choice of which chemical modification to use is responsible for the biotin reagent binding to a specific protein.<ref name=ThermoFisher /> Second, the sample is incubated with avidin bound to beads, then rinsed, removing all unbound proteins, while leaving only the biotinylated protein bound to avidin. Last, the biotinylated protein can be eluted from the beads with excess free biotin.<ref>{{cite journal | vauthors = Morag E, Bayer EA, Wilchek M | title = Immobilized nitro-avidin and nitro-streptavidin as reusable affinity matrices for application in avidin-biotin technology | journal = Anal Biochem | volume = 243 | issue = 2 | pages = 257–263 | date = Dec 1996 | pmid = 8954558 | doi = 10.1006/abio.1996.0514 }}</ref> The process can also utilize bacteria-derived [[streptavidin]] bound to beads, but because it has a higher dissociation constant than avidin, very harsh conditions are needed to elute the biotinylated protein from the beads, which often will denature the protein of interest.<ref name=Laitinen2006/>