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  • A2547 - Monoclonal Anti-Actin, α-Smooth Muscle

A2547 Sigma-Aldrich

Monoclonal Anti-Actin, α-Smooth Muscle

clone 1A4, ascites fluid

Synonym: Alpha Smooth Muscle Actin Antibody - Monoclonal Anti-Actin, α-Smooth Muscle, Alpha Smooth Muscle Actin Antibody Sigma, Anti-Alpha Smooth Muscle Actin Antibody, SMA

  •  NACRES NA.41



Related Categories AC-AC, Alphabetical Index, Antibodies, Antibodies for Cell Biology, Antibodies to Actin Isoforms,
conjugate   unconjugated
clone   1A4, monoclonal
biological source   mouse
application(s)   immunohistochemistry (formalin-fixed, paraffin-embedded sections): suitable using smooth muscle cells
  immunohistochemistry (frozen sections): suitable using smooth muscle cells
  indirect immunofluorescence: 1:400 using blood vessels in sections of human appendix
  western blot: suitable using smooth muscle cells
species reactivity   human, frog, sheep, chicken, goat, bovine, rat, guinea pig, mouse, canine, rabbit, snake
mol wt   antigen ~42 kDa
shipped in   dry ice
storage temp.   −20°C
antibody form   ascites fluid
isotype   IgG2a
antibody product type   primary antibodies
contains   15 mM sodium azide
Featured Industry   Research Pathology
UniProt accession no.   P62736
Gene Information   human ... ACTA2(59)
mouse ... Acta2(11475)
rat ... Acta2(81633)


General description

Actins are cytoskeletal proteins that regulate cell motility. Several scaffolding, signaling and actin-binding proteins regulate the interconversions between filamentous F-actins and monomeric G-actins. Cellular actins of various species have very similar immunological and physical properties. Hence, the use of monoclonal antibody to actin provides a specific and useful tool for studying the localization, structure and function of actin proteins. Actin 2 (ACTA2), the smooth muscle actin is encoded on human chromosome 10q23.31.
Mouse monoclonal anti-actin, α-smooth muscle antibody binds to actin from human, mouse, rat, bovine, chicken, frog, goat, guinea pig, rabbit, dog, sheep, and snake.
Monoclonal Anti-α Smooth Muscle Actin (mouse IgG2a isotype) is derived from the hybridoma produced by the fusion of mouse myeloma cells and splenocytes from an immunized mouse. The NH2 terminal synthetic decapeptide of α-smooth muscle actin coupled to keyhole limpet hemocyanin (KLH) was used as the immunogen. The isotype is determined using Sigma ImmunoTypeTM Kit (Sigma Stock No. ISO-1) and by a double diffusion immunoassay using Mouse Monoclonal Antibody Isotyping Reagents (Sigma Stock No. ISO-2).

The antibody (also known as anti-α-Sm-1) is specific for the single isoform of α-smooth muscle actin. It reacts specifically with α-smooth muscle actin in immunoblotting assays and labels smooth muscle cells in frozen or formalin-fixed, paraffin-embedded tissue sections.


Monoclonal Anti-α Smooth Muscle Actin is specific for the single isoform α-actin. It reacts specifically with a smooth muscle actin using immunoblotting and indirect immunofluorescent labeling of formalin-fixed, paraffin embedded or frozen tissue sections. The antibody can be used for immunocytochemical localization of the α smooth muscle actin by means of immunoperoxidase, immunofluorescent, ELISA or immunoblot techniques. The antibody reacts with human, mouse, rat, bovine, chicken, frog, goat, guinea pig, rabbit, dog, sheep, and snake.


N-terminal synthetic decapeptide of α-smooth muscle actin.


Immunocytochemistry was performed on smooth muscle cells from bovine aortas using the monoclonal anti-ACTA2 antibody. Cells were first grown on glass cover slips and fixed in 50% acetone/EtOH for 10 minutes at 4 degrees.

Mouse monoclonal anti-actin, α-smooth muscle antibody has been used for western blot assays using whole kidney homogenates in human anaplastic thyroid cancer cells. The product has also been used for immunohistochemical assays using mice tissue sections in liver sections and uterine sections.
Monoclonal Anti-Actin, α-Smooth Muscle antibody has been used in the detection of actin 2 in breast fibroblasts using immunofluorescence staining.

Paraffin embedded sections of rat testis tissue grafts were immunohistochemically stained with mouse monoclonal anti-smooth muscle actin.
IHC analysis of x-gal stained muouse cardiac tissue was performed using the primary antibody, mouse monoclonal anti-smooth muscle actin to identify myofibroblasts.

Physical form

The antibody is provided as ascites fluid containing 15mM sodium azide as a preservative.

Storage and Stability

For continuous use, store at 2-8 °C for up to one month. For extended storage, solution may be frozen in working aliquots. Repeated freezing and thawing is not recommended. If slight turbidity occurs upon prolonged storage, clarify by centrifugation before use.


Unless otherwise stated in our catalog or other company documentation accompanying the product(s), our products are intended for research use only and are not to be used for any other purpose, which includes but is not limited to, unauthorized commercial uses, in vitro diagnostic uses, ex vivo or in vivo therapeutic uses or any type of consumption or application to humans or animals.

Biochem/physiol Actions

Actin is one of the most conserved eukaryotic proteins, it is expressed in mammals and birds as six isoforms characterized by electrophoresis and amino acid sequence analysis. Four of the six represent differentiation markers of muscle tissues. Actin isoforms show >90% overall sequence homology, but only 50-60% homology in their 18 NH2-terminal residues. The NH2-terminal region of actin appears to be a major antigenic region, and may be involved in the interaction of actin with other proteins such as myosin. It has been shown that the relative proportion of actin isoforms are different in smooth muscles of different organs and change within the same population of smooth muscle cells during development, pathological situations and different culture conditions.
Mutations in actin 2 is associated with dysfunction of smooth muscles in arteries and is implicated in coronary heart disease. Mutations in ACTA2 contributes to tear and enlargement of aorta in thoracic aortic aneurysms (TAAD).

Other Notes

To view an Actin antibody selection guide, please visit www.sigmaaldrich.com/actin.

Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable

Frequently Asked Questions

Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.
What is the molecular weight of actin, ProductsA2066 and A2547?
Actin has a molecular weight of 42 kDa.
Why do I have 3 bands on my western blot when using Product A2547, Monoclonal Anti-Actin, α-Smooth Muscle antibody produced in mouse?
While actin should run as a 42 kDa band when detected by Western blotting, there are recent observations that cleavage products can be seen in cells undergoing apoptosis. Initial cleavage gives a band at 41 kDa, which may appear as a doublet on the blot. In addition, further cleavage results in a major band at 30 kDa and a small band at 14 kDa which have been shown to be cleavage products due to the action of interleukin 1 -converting enzyme. This may explain the detection of smaller bands when blotting with this antibody. This banding pattern may be detected with other actin antibodies as well. Kayalar, C., et al., Proc. Natl. Acad. Sci., USA, 93:2234-2238, (1996).
What is the antibody concentration of Product A2547, Monoclonal Anti-Actin, α-Smooth Muscle antibody produced in mouse?
This antibody is ascities fluid. The amount of protein present and the amount of IgG1 present is indicated on the Lot-specific Certificate of Analysis.
Is there a protocol for using Product A2547, Monoclonal Anti-Actin, α-Smooth Muscle antibody produced in mouse, in immunohistochemistry?
This antibody is used in our Immunohistochemistry Kit, Product No. IMMH2.
How do I get lot-specific information or a Certificate of Analysis?
The lot specific COA document can be found by entering the lot number above under the "Documents" section.
How do I find price and availability?
There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote. USA customers: 1-800-325-3010 or view local office numbers.
What is the Department of Transportation shipping information for this product?
Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product.
Can Product A2547,Monoclonal Anti-Actin, α-Smooth Muscle antibody detect beta actin?
No, Product A2547, Monoclonal Anti-Actin, α-Smooth Muscle antibody will not cross react with beta actin.
My question is not addressed here, how can I contact Technical Service for assistance?
Ask a Scientist here.
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Protocols & Articles


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