Aorrayong |
ตอบ: 05/02/2010 8:15 pm ชื่อกระทู้: |
|
ที่มา คัดลอกจากhttp://en.wikipedia.org/wiki/Glucosamine
Glucosamine
From Wikipedia, the free encyclopedia
Glucosamine (C6H13NO5) is an amino sugar and a prominent precursor
in the biochemical synthesis of glycosylated proteins and lipids.
Glucosamine is part of the structure of the polysaccharides chitosan and
chitin, which compose the exoskeletons of crustaceans and other
arthropods, cell walls in fungi and many higher organisms.
Glucosamine is one of the most abundant monosaccharides.[1] It is
produced commercially by the hydrolysis of crustacean exoskeletons or,
less commonly by fermentation of a grain such as corn or wheat.[citation
needed] In the US it is one of the most commonly used non-vitamin, non-
mineral, natural products used by adults as a complementary or
alternative medicine.[2
Biochemistry
Glucosamine was first prepared in 1876 by Dr. Georg Ledderhose by the
hydrolysis of chitin with concentrated hydrochloric acid.[3][4] The
stereochemistry was not fully defined until the 1939 work of Walter
Haworth.[1] D-Glucosamine is made naturally in the form of glucosamine-
6-phosphate, and is the biochemical precursor of all nitrogen-containing
sugars.[5] Specifically, glucosamine-6-phosphate is synthesized from
fructose 6-phosphate and glutamine[6] as the first step of the
hexosamine biosynthesis pathway.[7] The end-product of this pathway is
UDP-N-acetylglucosamine (UDP-GlcNAc), which is then used for making
glycosaminoglycans, proteoglycans, and glycolipids.
As the formation of glucosamine-6-phosphate is the first step for the
synthesis of these products, glucosamine may be important in regulating
their production; however, the way that the hexosamine biosynthesis
pathway is actually regulated, and whether this could be involved in
contributing to human disease remains unclear.[8] |
|