Proteins are the engines of the biological world. A diverse set of 20 different amino acids, each with unique features, combine in linear polypeptide polymers to form ‘power houses’ with a wide range of capabilities. Proteins cut and fuse other molecules, act as transport vehicles, transform energy, act as structural building blocks and more. In addition to their significance in the natural world, proteins also have many important industrial applications.

To celebrate Sigma’s great portfolio of protein products, throughout 2017, we will feature 12 protein ‘power-houses’ which showcase the diversity and capabilities of proteins. Search through the wide range of Sigma enzyme and protein products, category indices and online bioinformatics tools on our Enzyme Explorer webpage!

Complete our Online Quiz to learn about these proteins and to win prizes too! You could win a selection of timestrip® indicators and a Lanyard. One lucky winner will also receive an iPad mini by telling us about their favourite protein at the end of the quiz.*

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2017 Archive  

Protein of the Month, August: laminin | human, e.g. L6274; and other laminins

Laminins are high-molecular weight (~400 to ~900 kDa) proteins of the extracellular matrix. They are a major component of the basal lamina (one of the layers of the basement membrane), a protein network foundation for most cells and organs. The laminins are an important and biologically active part of the basal lamina, influencing cell differentiation, migration, and adhesion.
The laminin family of glycoproteins are an integral part of the structural scaffolding in almost every tissue of an organism. Laminin is vital for the maintenance and survival of tissues. Defective laminins can cause muscles to form improperly, leading to a form of muscular dystrophy, lethal skin blistering disease (junctional epidermolysis bullosa) and defects of the kidney filter (nephrotic syndrome).

[Source: Wikipedia - Image: Mosby's Medical Dictionary,8th edition. 2009. Elsevier 12 Jul. 2017]
Laminins in cell culture
Recently, several publications have reported that laminins can be used to culture cells, such as pluripotent stem cells, that are difficult to culture on other substrates. Mostly, two types of laminins have been used. Laminin-111 extracted from mouse sarcomas is one popular laminin type, as well as a mixture of laminins 511 and 521 from human placenta.
Laminin supports growth and differentiation of many cell types including epithelial, endothelial, neural, muscle and liver cells. It is recommended for use as a cell culture substratum at 1-2 μg/cm2. The optimal concentration does depend on cell type as well as the application or research objectives.
Did you know? How do you prepare Laminin from human placenta? (L6274)
To prepare a laminin solution, we recommend that the L6274 be thawed at 2-8°C to avoid the formation of a gel. This can be further diluted in a balanced salt solution. If the product has been thawed at room temperature and ends up as a gel, it cannot be reactivated for use.
Take part in our Catalyzing Online Proteins and Enzymes Quiz to find a discount promo code!

2016 Archive  


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One quiz entry per person. Quiz entry valid for customers in Europe, Middle East and Africa only. All quiz entries must be submitted by 31st December 2017.