• Product name

  • Expression system

    Escherichia coli
  • Protein length

    Full length protein
  • Animal free

  • Nature

    • Species

      Escherichia coli
  • Description

    Native E. coli beta Galactosidase protein


Our Abpromise guarantee covers the use of ab79449 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

  • Form

  • Additional notes

    Beta Galactosidase was prepared chromatographically. This product has been sterile filtered. Beta Galactosidase is used as a control in beta-galactosidase based immunological assays. 

    Beta-galactosidase, also called beta-gal or Beta-gal, is a hydrolase enzyme that catalyzes the hydrolysis of Beta-galactosides into monosaccharides. Substrates of different Beta-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins. Lactase is often confused as an alternative name for Beta-galactosidase, but it is simply a sub-class of Beta-galactosidase. Beta-galactosidase is an exoglycosidase which hydrolyzes the Beta-glycosidic bond formed between a galactose and its organic moiety. It may also cleave fucosides and arabinosides but with much lower efficiency. It is an essential enzyme in the human body, deficiencies in the protein can result in galactosialidosis or Morquio B syndrome. In E. coli, the gene of Beta-galactosidase, the lacZ gene, is present as part of the inducible system lac operon which is activated in the presence of lactose when glucose level is low.

    It is commonly used in molecular biology as a reporter marker to monitor gene expression. It also exhibits a phenomenon called alpha-complementation which forms the basis for the blue/white screening of recombinant clones. This enzyme can be split in two peptides, LacZ-alpha and LacZ-omega neither of which is active by itself but when both are present together, spontaneously reassemble into a functional enzyme. This property is exploited in many cloning vectors where the presence of the lacZ-alpha gene in a plasmid can complement in trans another mutant gene encoding the LacZ-omega in specific laboratory strains of E. coli. However, when DNA fragments are inserted in the vector, the production of LacZ-alpha is disrupted, the cells therefore show no Beta-galactosidase activity. The presence or absence of an active Beta-galactosidase may be detected by X-gal, which produces a characteristic blue dye when cleaved by Beta-galactosidase, thereby providing an easy means of distinguishing the presence or absence of cloned product in a plasmid.


  • Concentration information loading...

Preparation and Storage

  • Stability and Storage

    Shipped at 4°C. Store at +4°C.

    pH: 7.80
    Constituents: 0.42% Potassium phosphate, 10% Sucrose

General Info

  • Alternative names

    • Beta D galactosidase
    • Beta gal
    • Beta galactosidase
    • ECK0341
    • JW0335
    • Lactase
    • lacZ
    see all
  • Relevance

    Beta galactosidase is coded by a gene (lac z) in the lac operon of Escherichia coli. It is a metalloenzyme that splits lactose into glucose and galactose. It hydrolyzes terminal, non-reducing beta-D-galactose residues in beta-D-galactosides. Activation by cations seems to be substrate dependent. K+, Na+, NH4+, Rb+, Cs+ and Mn++ all activate enzyme activity based upon the substrate used.
  • Cellular localization



This product has been referenced in:

See 1 Publication for this product

Customer reviews and Q&As

1-4 of 4 Abreviews or Q&A


Thank you for contacting us on Friday of last week. I am sorry for the delay in getting back to you.

As discussed over the phone I have looked into the activity of the beta Galactosidase protein (ab79449). We do not have precise activity data available for this product. However, it generally has 250-400 units of activity per unit of protein.

The product is designed as a control for immunological assays and we are therefore not able to guarantee the specific activity for the product. However, if you would like to try ab79449, I would be able to offer you an Abtrial testing discount.

This offer means that if you purchase ab79449 as normal, test the protein in your activity assay and let us know of the results through an Abreview (no matter whether positive or negative) you would then be eligible to claim the value of ab79449 off any product in our catalogue. More information on this offer can be found here:

Please note that the product to be tested must be purchased, tested, the Abreview submitted and the free product claimed within a 4 month period.

If you would be interested in participating in this scheme please do let me know as a discount code needs to be issued prior to the purchase of ab79449.

I hope this information has been of help. If you require any further information please do not hesitate to contact us again.

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It is an active protein, the assay we use to determine activity is Beta galactosidase assay. We have not sequenced this product but it is sourced from E coli and should be similar to P00722 ( It is sold as 5000 units and one unit is defined as one Unit hydrolyzes one micromole fo p-nitrophenyl-B-D-galacotpyranoside per minute at 25deg.C, pH 7.5


This product is native protein from Escherichia coli and a sequence is not determined. The level of enzymatic activity is not guaranteed, but the enzyme was tested for activity using 2-nitrophenyl-b-galctoside and/or 4- nitrophenyl b D-galactoside.

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Thank you for your enquiry and interest in our products.

I can confirm that these two products (ab7981 and ab79449) are not His-tagged. I have checked our catalogue and currently we only sell non-tagged beta Galactosidase protein.

If you need any further assistance in the future, please do not hesitate to contact me.

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Thank you for your inquiry. I am afraid that these products, ab7981 and ab79449, does not contain a His tag. If there is anything else that I can help you with, please do not hesitate to contact me.

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