Hyaluronan synthase enzymes synthesize large, linear polymers of the repeating disaccharide structure of hyaluronan by alternating addition of glucuronic acid and N-acetylglucosamine to the growing chain using their activated nucleotide sugars (UDP – glucuronic acid and UDP-N-acetlyglucosamine) as substrates (Meyer and Palmer, 1934).
The number of repeat disaccharides in a completed hyaluronan 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 ~1 nm. Thus,a hyaluronan molecule of 10 000 repeats could extend 10 µm if stretched from end to end, a length
approximately equal to the diameter of a human
erythrocyte (Cowman and Matsuoka, 2005)