Isotype, western blotting and lysate loading controls

In order to evaluate any experiment, it is important to include both appropriate positive and negative controls in your experimental design. To make this task easier Abcam offers a large selection of ready-to-use controls.

Isotype loading controls

Isotype controls are used to confirm that the primary antibody binding is specific and not a result of non-specific Fc receptor binding or other protein interactions. The isotype control antibody should match the primary antibody’s host species, isotype, and conjugation. Our monoclonal and polyclonal isotype loading controls are tested in various applications such as western blotting, flow cytometry and ELISA and come from a variety of species:

• Chicken
• Goat
• Hamster
• Mouse
• Rabbit
• Rat
• Sheep

Loading controls

All lanes: beta Actin antibody (ab8229) at 1/1000 dilution

Lane 1 : HeLa lysate, Lane 2 : 3T3 lysate, Lane 3 : Rabbit Liver,
Lane 4 : MDCK lysate, Lane 5 : EBTr lysate, Lane 6 : SL-29 lysate,
Lane 7 : CHO lysate

The main use of loading controls is in western blotting: to ensure that the lanes in your gel contain the same amount of sample and that the transfer onto the membrane was equal. Especially, when a comparison is made between the expression of a protein in different samples, a loading control is absolutely essential. Apart from western blotting, loading controls are essential to confirm that alterations in protein levels are due to an effective "knock-out" or "knock-down" and not just due to general changes in gene expression or protein synthesis.

View our entire range of loading controls comprising:

• beta actin - including beta actin - loading control antibody (ab8229) (see image)
• Chromatin
• COX IV mitochondrial
• GADPH
• TBP-Nuclear
• Tubulin
• VDAC1-mitochondrial preps

Lysates

Lane1 : Acid-extracted proteins from chicken erythrocyte nuclei
Lane2 : Chicken-erythrocyte nuclear lysate (ab45274)

If you would like to detect a protein for the first time on a western blot and you do not know if and when the protein is expressed, it is advisable to include a positive control. Abcam lysates make great positive controls as the proteins present in our lysates are well documented and you can choose from over 2100 products from a variety of tissue types, species, and disease states:

• 293T transfected - over 300 lysates transfected with different immunology, cardiovascular and apoptosis markers - such as annexin-V
• Cytoplasmic - over 160 lysates from various tissues including brain, breast, colon, ovaries, pancreas and heart
• Membrane - 130 lysates from healthy and diseased tissues
• Nuclear - 224 lysates from many tissue types and cells lines; including cancer cell lines like HeLa, HepG2 and Jurkat
• Tissue - over 900 lysates from 24 different tissue types
• Total protein - to determine whether your protein is expressed in adipose tissue
• Whole cell - nearly 400 lysates for cancer, cardiovascular, immunology and neuroscience targets