2,695
edits
Lidstrom:Buffers: Difference between revisions
From OpenWetWare
Jump to navigationJump to search
→Notes specific to buffers
(→Q&A) |
|||
| Line 109: | Line 109: | ||
* Phosphates, for example, form insoluble salts with bivalent metals and precipitate. Phosphate buffered salt solution (PBS) is never autoclaved with Ca2+ or Mg2+ for this reason. Good buffers, such as PIPES, TES, HEPES and CAPS have very low metal-binding constants and are therefore particularly suited to investigate metal-dependent enzymes (Good & Izawa 1972, Blanchard 1984). [http://www.applichem.com/fileadmin/Broschueren/BioBuffer.pdf Applichem] | * Phosphates, for example, form insoluble salts with bivalent metals and precipitate. Phosphate buffered salt solution (PBS) is never autoclaved with Ca2+ or Mg2+ for this reason. Good buffers, such as PIPES, TES, HEPES and CAPS have very low metal-binding constants and are therefore particularly suited to investigate metal-dependent enzymes (Good & Izawa 1972, Blanchard 1984). [http://www.applichem.com/fileadmin/Broschueren/BioBuffer.pdf Applichem] | ||
*Phosphates and pyrophosphate are both substrates and inhibitors of different enzyme reactions (inhibition of carboxypeptidase, urease, various kinases, various dehydrogenases). [http://www.applichem.com/fileadmin/Broschueren/BioBuffer.pdf Applichem] | *Phosphates and pyrophosphate are both substrates and inhibitors of different enzyme reactions (inhibition of carboxypeptidase, urease, various kinases, various dehydrogenases). [http://www.applichem.com/fileadmin/Broschueren/BioBuffer.pdf Applichem] | ||
=== Tris buffer === | |||
* Tris buffer: not always the best choice! See [http://www.applichem.com/fileadmin/Broschueren/BioBuffer.pdf Applichem handout] | |||
** high degree of temperature-sensitivity; pH decreases by 0.1 unit with each 10fold dilution | |||
** inactivates DEPC, can form Schiff’s bases with aldehydes/ketones, as it is a primary amine | |||
** is involved in some enzymatic reactions (e.g. alkaline phosphatase) See [http://www.applichem.com/fileadmin/Broschueren/BioBuffer.pdf Applichem handout] | |||
== HEPES buffer === | |||
* can form radicals, not suitable for redox studies. See [http://www.applichem.com/fileadmin/Broschueren/BioBuffer.pdf Applichem handout] | |||
