Beta-galactosidase: Difference between revisions
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#Ullmann-Bioessays-1992 pmid=1345751 | #Ullmann-Bioessays-1992 pmid=1345751 | ||
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[[Category:Material]] [[Category:Reporter]] |
Revision as of 10:01, 26 July 2007
Some interesting facts [1]
- A tetramer of 4 identical subunits
- Each subunit is 120kD.
- Active only as a tetramer.
- Mutations in some of the codons of the N-terminal 60aa or C-terminal 100aa results in an inactive, dimeric β-galactosidase. [2]
- If the above sequences are deleted, the missing protein fragment can be replaced by the corresponding peptide. This is called intracistronic alpha or omega complementation respectively.
- Its N-terminal 23 residues can be replaced by any amino acid residues without affecting the enzymatic activity.
- A mutant with an internal deletion of codons 21-41 of the lacZ gene does not produce any active β-galactosidase.
- A mutant with a deletion of everything past residue 60 (i.e. it expresses only the first 60 N-terminal amino acids) does not produce any active β-galactosidase.