ST3GAL4 transfers Neu5Ac to terminal Gal of N-glycans

Stable Identifier
Reaction [transition]
Homo sapiens
Addition of alpha-2,3-sialic acid to N-glycan over a galactose by ST3GAL4
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Addition of sialic acid (Neu5Ac) to galactose-containing N-glycan. Neu5Ac is usually found at terminal positions of the N-glycan. This imparts a negative charge at neutral pH which affects the chemico-physical and biological properties of the N-glycans (for a review, see Schauer 2000); moreover, this modification can lead to the addition of extraordinarily long antennae such as polysialic acid (hundreds of sials) or polylactosamine repeats (dozens of disaccharide repeats) (Harduin-Lepers 2001), while the number of modifications on the antennae of N-glycans is usually lower.
There are over 20 sialyltransferases known in humans, 5 of which are known to act on N-glycans. Beta-galactoside alpha-2,6-sialyltransferase 1 (ST6GAL1) is the only sialyltransferase known to transfer Neu5Ac to galactose (Gal) on N-Glycans (Dall'Olio 2000). A second beta-Galactoside alpha-2,6-sialyltransferase has been characterized, but this enzyme acts mainly on oligosaccharides (Krzewinski-Recchi et al. 2003). Neu5Ac can also be added via an alpha-2,3-linkage to Gal on N-glycans by CMP-N-acetylneuraminate-beta-galactosamide-alpha-2,3-sialyltransferase 4 (ST3GAL4) (Ellies et al. 2002). ST8Sia II (ST8SIA2), ST8Sia III (ST8SIA3), and ST8Sia IV (ST8SIA6) have alpha-2,8-activity (Angata et al. 1997, Angata et al. 2000; Angata & Fuduka 2003).
Literature References
PubMed ID Title Journal Year
11425186 The sialyl-alpha2,6-lactosaminyl-structure: biosynthesis and functional role

Dall'Olio, F

Glycoconj J 2000
11530204 The human sialyltransferase family

Vallejo-Ruiz, V, Harduin-Lepers, A, Delannoy, P, Samyn-Petit, B, Krzewinski-Recchi, MA, Julien, S

Biochimie 2001
10766765 Differential biosynthesis of polysialic acid on neural cell adhesion molecule (NCAM) and oligosaccharide acceptors by three distinct alpha 2,8-sialyltransferases, ST8Sia IV (PST), ST8Sia II (STX), and ST8Sia III

Fukuda, M, Suzuki, M, Hindsgaul, O, Angata, K, Ding, Y, McAuliffe, J

J Biol Chem 2000
11421344 Achievements and challenges of sialic acid research

Schauer, R

Glycoconj J 2000
12603328 Identification and functional expression of a second human beta-galactoside alpha2,6-sialyltransferase, ST6Gal II

Teintenier-Lelièvre, M, Harduin-Lepers, A, Mir, AM, Delannoy, P, Samyn-Petit, B, Cerutti, M, Krzewinski-Recchi, MA, Juliant, S, Julien, S, Montiel, MD

Eur J Biochem 2003
12097641 Sialyltransferase ST3Gal-IV operates as a dominant modifier of hemostasis by concealing asialoglycoprotein receptor ligands

Marth, JD, Ellies, LG, Varki, A, Wahrenbrock, M, Le, DT, Ginsburg, D, Ditto, D, Levy, GG

Proc Natl Acad Sci U S A 2002
12765789 Polysialyltransferases: major players in polysialic acid synthesis on the neural cell adhesion molecule

Fukuda, M, Angata, K

Biochimie 2003
9054414 Human STX polysialyltransferase forms the embryonic form of the neural cell adhesion molecule. Tissue-specific expression, neurite outgrowth, and chromosomal localization in comparison with another polysialyltransferase, PST

Fukuda, M, Fredette, B, Nakayama, J, Angata, K, Chong, K, Ranscht, B

J Biol Chem 1997
Catalyst Activity

beta-galactoside (CMP) alpha-2,3-sialyltransferase activity of ST3GAL4 [Golgi membrane]

Orthologous Events
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