Agarose

Structural formula
General
Surname	Agarose
other names	(1 → 4) -3,6-anhydro-α- L -galactopyranosyl- (1 → 3) -β- D -galactopyranan
CAS number	9012-36-6
Monomers	D- galactose and 3,6- anhydro - L- galactose
Molecular formula of the repeating unit	C 12 H 18 O 9
Molar mass of the repeating unit	306.27 g mol −1
PubChem	11966311
Type of polymer	Biopolymer
Brief description	whitish yellow, odorless solid
properties
Physical state	firmly
density	≈ 0.9 g / cm 3
Melting point	88 ° C
solubility	easily soluble in water (when heated)
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Agarose is a polysaccharide made from D- galactose and 3,6- anhydro - L- galactose, which are glycosidically linked. It is the main component of agar and is mainly obtained from the red algae genera Gelidium and Gracillaria . In contrast to agar, the purified agarose contains far fewer negative charges . Agarose is a powerful gelling agent and is responsible for the agar's ability to gel .

Agarose gel is the name for a gel that is used in agarose gel electrophoresis for the electrophoretic separation of substances, e.g. B. is used by nucleic acids or proteins . It is prepared by boiling agarose in a buffer , for example in TBE buffer , in TAE buffer or in LB buffer . The concentration of the agarose in the buffer depends on the size of the particles to be separated with the gel electrophoresis, whereby a better separation (spatial resolution) can be achieved for smaller particles with a higher percentage agarose gel, for larger particles with a lower percentage gel. For the agarose gel electrophoresis of plasmids and their restriction fragments , for example, a concentration of 0.7 to 1.2% agarose in the gel buffer is usually used.

Agarose concentration in% (w / v)	Separation area in bp
0.5	1000-30000
0.7	800-12000
1.0	500-10000
1.2	400-7000
1.4	200-4000
2.0	50-2000

Special formaldehyde- containing gels must be used to separate RNA . Auxiliaries are often added to the gels during production to make the separated molecules visible. In the case of DNA, this is mostly ethidium bromide .

Further applications of agar or agarose relate to techniques of immunodiffusion ( Ouchterlony test or Ouchterlony double immunodiffusion ) or immunoelectrophoresis . Cross-linked agarose under the trade name Sepharose sold, the for Se paration- Pha rmacia-aga rose stands. Sepharose is used as a stationary phase for the chromatographic separation of biomolecules. With Protein A or Protein G Sepharose beads coated ( English beads ) are used in the immunoprecipitation used.

The world's largest agarose powder production facility, Lonza Rockland is located in Rockland, Maine .

literature

• Jeremy M. Berg, John L. Tymoczko, Lubert Stryer : Biochemistry. 6 edition, Spektrum Akademischer Verlag, Heidelberg 2007. ISBN 978-3-8274-1800-5 .
• Donald Voet, Judith G. Voet: Biochemistry. 3rd edition, John Wiley & Sons, New York 2004. ISBN 0-471-19350-X .
• Bruce Alberts , Alexander Johnson, Peter Walter, Julian Lewis, Martin Raff, Keith Roberts: Molecular Biology of the Cell , 5th Edition, Taylor & Francis 2007, ISBN 978-0815341062 .

Individual evidence

1. ↑ ^{a b c} Agarose data sheet (PDF) from Carl Roth , accessed on December 14, 2010.
2. ↑ Agarose data sheet , PFGE at Avantor Performance Materials , accessed on October 9, 2014.
3. ↑ Data sheet page no longer available , search in web archives: Agarose MP (PDF; 63 kB) at AppliChem , accessed on October 9, 2014.
4. ↑ Rockland, ME (USA). Lonza Locations Worldwide, accessed November 17, 2017.