Comigration standard
As a molecular-weight size marker or Comigrationsstandard (colloquially size markers , size ladder ) is referred to in the biochemistry and molecular biology, a sample of known composition in gel electrophoresis , or gel permeation chromatography is used separation method, a size comparison of the molecules in the sample to enable unknown composition. The migration of the substances contained, for example proteins or DNA , in the sample of known composition (protein or DNA conductor ) is compared with the migration of the sample of unknown composition. The same migration distance in the gel indicates the same electrophoretic running properties. The same running properties can be achieved with gel electrophoresis, which have a direct connection between the electrophoretic mobility and the molar mass (e.g. proteins via SDS-PAGE , DNA and RNA via agarose gel electrophoresis ) to determine the molar mass of the molecules contained in the sample be used.
DNA markers
DNA markers are used in agarose gel electrophoresis and polyacrylamide gel electrophoresis . One of the earlier DNA markers was bacteriophage λ DNA cut with the restriction enzyme Hind III . Another DNA marker was the DNA cut with HaeIII from bacteriophage X174. The sizes of the fragments were at irregular distances from one another. By ligation of fragments 100 base pairs in length, a DNA ladder with these same distances can be created. Longer DNA sequences with regular restriction cleavage sites were also generated by polymerase chain reaction (PCR) and then partially cut with the restriction endonuclease SmaI . Furthermore, exclusively PCR-based methods for generating DNA ladders were developed.
Protein markers
Typical proteins in protein markers
| protein | Molar mass in an SDS-PAGE ( kDa ) |
| Beta-galactosidase | 120 |
| Phosphorylase B | 94 |
| Bovine Serum Albumin (BSA) | 67 |
| Ovalbumin | 42.8 |
| Turkey - albumin | 40 |
| Carbonic anhydrase | 30th |
| Soy - trypsin inhibitor | 20.1 |
| α-lactalbumin | 14.4 |
| Lysozyme | 14th |
literature
- Friedrich Lottspeich , Joachim W. Engels (Ed.): Bioanalytik . 2nd edition, Spektrum Akademischer Verlag, Heidelberg 2006, ISBN 978-3827415202 .
- Hubert Rehm , Thomas Letzel: The Experimenter: Protein Biochemistry / Proteomics . 6th edition, Spektrum Akademischer Verlag, Heidelberg 2009. ISBN 978-3-8274-2312-2 .
- Cornel Mülhardt: The Experimenter: Molecular Biology / Genomics. Sixth edition. Spectrum Akademischer Verlag, Heidelberg 2008. ISBN 3-8274-2036-9 .
Individual evidence
- ↑ Vo Thi Thuong Lan, Pham Thi Thanh Loan, Pham Anh Thuy Duong, Le Thi Thanh, Ngo Thi Ha, Ta Bich Thuan: Straightforward Procedure for Laboratory Production of DNA Ladder. In: Journal of Nucleic Acids. 2012, 2012, p. 1, doi : 10.1155 / 2012/254630 .
- ↑ MohammadReza Mofid, Mahdi Abbasian, Hadieh Alsadat Eslampanah Seyedi, ZahraKhalili Boroujeni: Easy method for production of a home-made DNA ladder in every laboratory. In: Advanced Biomedical Research. 4, 2015, p. 70, doi : 10.4103 / 2277-9175.153894 . PMID 25878995 .
- ↑ Saied Mostaan, Mehdi Ajorloo, Hossein Khanahmad, RezaAhangari Cohan, ZahraRikhtegaran Tehrani, Maryam Rezaei, Fateme Fazeli, Mehdi Behdani, SakinehKarimi Zare, Zeinab Karimi, Seyed Mozhgani, Rasul Moukhah method for ladders benefit combined novel production. In: Advanced Biomedical Research. 4, 2015, p. 15, doi : 10.4103 / 2277-9175.148298 . PMID 25625121 .
- ↑ T.-Y. Wang, L. Wang, F. Wang: Methodology Simplified preparation of a DNA ladder using PCR. In: Genetics and Molecular Research. 10, 2011, p. 1631, doi : 10.4238 / vol10-3gmr1177 .
- ↑ weight-marker / Prestained Protein Molecular Weight Marker. . In: ThermoScientific . Retrieved November 12, 2013.
- ↑ a b c d e Margareta Ingelman: Courses% 2FKE7001per3% 2FLabs% 2Fprot_purana_lab_05.doc Protein separation and analysis . In: KE7001 Biochemistry Labs . 2004. Retrieved November 12, 2013.
- ^ Protein Molecular Weight Markers . In: Help Biotech . 2011. Retrieved November 12, 2013.