Proteoglycans with E-unit structures: Structure, function and health benefits

Proteoglycans with E-unit structures are particularly noteworthy among proteoglycans. They play a role in water retention and buffering within the body.​

Proteoglycans are important components of the extracellular matrix (ECM), consisting of core proteins linked with many polysaccharides. They are widely distributed in cartilage, skin, ligaments and basement membranes where they play a role in water retention and buffering within the body.

The function of proteoglycans is usually lubrication and buffering, due to their  water retention ability, but in recent years, a variety of functions have been elucidated. The structure of proteoglycans consists of a core protein (proteo) to which many polysaccharides (glycans) are bound, but in the case of animal proteoglycans, amino sugars (glycosaminoglycans) are bound as polysaccharides (glycans) to the core protein (proteo).

The chondroitin sulfate structure, which is a representative amino sugar, is a structural component that significantly influences the diverse functions of proteoglycans. Its basic structure consists of N-acetylgalactosamine (GalNAc) and glucuronic acid (GlcA), forming a disaccharide unit that is bonded in a chain shape.

The length of the disaccharide chain is 50 to 200 units, and the sulfate group bonds are nonuniform. In other words, PGs are diverse molecules due to the mixture of various unit structures. This is a major difference from DNA and RNA, which have uniform sequences.

Proteoglycans with E-unit structures are characterised by a sulfate group bound at both the 4th and 6th positions of GalNAc. This structure greatly enhances the functionality of the proteoglycans. Unlike other unit structures (such as A-type or C-type), the E-unit structure, with its two sulfate groups, has been confirmed to exhibit a higher level of physiological activity. Due to their effectiveness even in small amounts, proteoglycans with E-unit structures are highly valued as an efficient means to maintaining good health.

In Japan, proteoglycans have been attracting attention since the 1970s, but they can only be obtained from limited parts of mammals, such as bovine tracheal cartilage and chicken combs. Therefore, they are costly to produce, and practical applications are far from being achieved.

In 1998, the mass extraction of proteoglycans with C-unit structures from salmon nasal cartilage (salmon head) achieved significant cost reductions, aiding the launch of a range of health food and cosmetic products into the market.^1,2​ In 2017, highly functional proteoglycans with E-unit structures were extracted from squid orbital cartilage, and they have since attracted increasing attention.

Medience Corporation has been researching and commercialising proteoglycans with E-unit structures, known to support joint health, suppress inflammation, and promote cell-level proliferation and formation, for both the nutraceutical and cosmetic markets.

Physiological activities of proteoglycans with E-Unit structure​

Proteoglycans are present in many organs and are known to regulate various physiological activities through chondroitin with various unit structures. In other words, they are thought to interact with various physiologically active factors, such as cell growth factors, cell differentiation factors, and cell adhesion factors. They can also exert various functions, such as cell proliferation, tissue formation and organ formation.

Proteoglycans with an E-unit structure, in which two sulfate groups are bonded, are thought to have following functions:

Strengthening cartilage, bones, and joints ​
Chondroitin with an E-unit structure (‘E-unit structure chondroitin’) is extracted from squid orbital cartilage. Its extraction rate is 2%, making it a very rare ingredient. E-unit structure chondroitin promotes the production of bone morphogenetic protein (BMP) and osteocalcin (OCN) – hormones involved in cartilage and bone formation –  and enhances the production of collagen and hyaluronic acid, strengthening cartilage, bones, and joints while also preserving skin moisture.

Anti-Inflammatory effects and joint pain relief​
E-unit structure chondroitin seizes the inflammatory factor midkine (MK), suppresses the attacking factor TGF-β, improves immune parameters (Th1/Th2 cell ratio), and cleaves CD44, thereby suppressing inflammation and relieving joint pain and swelling.

Increase in male hormones and insulin secretion​
E-unit structure chondroitin increases the secretion of testosterone and insulin by promoting the production of osteocalcin (OCN).

Elongation of nerve cells​
E-unit structure chondroitin has been shown to promote the elongation of nerve processes, which can repair central nervous system damage and is expected to improve memory, prevent dementia, and enhance vision. These effects are specific to chondroitin with E-unit structures.

Applications and potential uses of proteoglycans

Proteoglycans with E-unit structures are increasingly applied in health foods and supplements due to their high functionality. While the daily dosage of proteoglycans with C-unit structures is 5 mg, those with E-unit structures are effective in even smaller amounts.

Thanks to their unique structure, proteoglycans with E-unit structures exhibit a wide range of positive effects. There is the expectation that these structures will be more effective against other symptoms besides that of just inflammation and joint pain, with their effects being further clarified through ongoing research.

Medience Corporation carefully selects raw materials and products with proven evidence, ensuring authenticity and delivering trust and peace of mind to its customers.

For more information visit ​Proteoglycans with an E-unit structure​.​

References​

1. ​Kakuhiro Corp., Takagaki K. Purification method for cartilage-type proteoglycan​. Patent No. 3731150 (21 Oct, 2005).
2. ​Hirosaki University. Extraction method for proteoglycan​. JP 2009-173702 (6 Aug, 2009).