Everything you need to know about Hyaluronic Acid (HA) and its Benefits
- HA is a high molecular weight Biopolysaccharide, discovered in 1934 by Karl Meyer and his assistant, John Palmer in the vitreous of bovine eyes. Hyaluronic Acid is a naturally occurring biopolymer, which has important biological functions in bacteria and higher animals including humans.It is found in most connective tissues and is particularly concentrated in synovial fluid, the vitreous fluid of the eye, umbilical cords and chicken combs.It is naturally synthesized by a class of integral membrane proteins called hyaluronan synthases and degraded by a family of enzymes called hyaluronidases. This review describes metabolisms, different physiological and pathological functions, basic pharmacological properties, and the clinical use of hyaluronic acid.
Keywords to abstract: hyaluronic acid, metabolism, and toxicity.
Hyaluronic acid (HA) is a carbohydrate, more specifically a mucopolysaccharide, occurring naturally in all living organisms. It can be several thousands of sugars long. When not bound to other molecules, it binds to water giving it a stiff viscous quality similar to " Jello". The polysaccharide hyaluronan (HA) is a linear polyanion, with a poly repeating disaccharide structure.HA is found primarily in the extracellular matrix and pericellular matrix but has also been shown to occur intracellularly. The biological function functions of HA include maintenance of an elastoviscosity of liquid connective tissues such as joint synovial and water transport, supramolecular assembly of proteoglycans in the extracellular matrix, and numerous receptor-mediated roles in cell detachment, mitosis, migration, tumor development and inflammation.
Polymer Structure
HA, synthase enzymes synthesize large, linear polymers of repeating disaccharide structure of hyaluronan by alternating by alternating addition of glucuronic acid and N- acetylglucosamine to the growing chain using their activated nucleotide sugars (UDP- glucuronic acid and UDP- N- acetylglucosamine) as substrates( Mayer & Palmer, 1934). The number of repeats disaccharides in completed HA molecule can reach 10 000 or more, a molecular mass of 4 million daltons ( each disaccharide is ~ 400 daltons). The average length of a disaccharide is ~1nm. Thus, an HA molecule of 10 000 repeats could expend 10um if stretched from end to end, a length almost equal to the diameter of a human erythrocyte (Cowman & Matsuoka, 2005).
Synthesis
The cellular synthesis of HA is a unique and highly controlled process.Most of them are made in the cell`s Golgi network. HA is naturally synthesized by a class of integral membrane proteins called hyaluronan synthases, of which vertebrates have HAS1, HAS2, and HAS3 ( Lee and Spicer,2000). Secondary structure predictions and homology modeling indicate an integral membrane protein (IMP). An integral membrane protein is a protein molecule( or assembly of proteins) that in most cases spans the biological membrane with which it is associated ( especially the plasma membrane) or which, is sufficiently embedded in the membrane to remain with it during the initial steps of biochemical purification ( in contrast to peripheral membrane proteins). HA, synthase enzymes large, linear polymers of the repeating disaccharide structure of hyaluronan by alternate addition of glucuronic acid and N- acetylglucosamine to the growing chain using their activated nucleotide sugars.
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