GGDB:

この酵素は、供与体基質UDP-GalNAcからタンパク質のセリンまたはスレオニン残基にGalNAcを転移する活性を持つ。反応生成物は広くTn-抗原として知られているGalNAc-alpha-O-Ser/Thr構造で、ムチン型O-グリカンの根本の構造である。受容体基質であるタンパク質の典型はムチンである。このアイソザイムはこのファミリーの4番目のメンバーである。このアイソザイムはGALNT2が生成するGalNAc修飾されたペプチドに対して強い活性を示す。

Keyword: O-グリカン , Tn抗原 , ムチン , 腫瘍マーカー

HO-Ser/Thr (Glycopeptide)	UDP-GalNAc	GalNAc(alpha1-O)-Ser/Thr (Glycopeptide)

UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase

GGDB Symbol

GALNT4 Alias

Designation

UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 4

Organism

Homo sapiens

GeneID

8693

HGNC

GALNT4 (4126)

mRNA

NM_003774

map

12q21.3-q22

Protein

NP_003765

EC#

2.4.1.41

CAZy

GT27

GlyCosmos Glycogenes

GALNT4

OMIM

603565

Disease name

GDGDB

Human Protein Atlas

ENSG00000257594

Mus musculus

mRNA	NM_015737
Protein	NP_056552
MGI	32962

Rattus norvegicus

mRNA	NM_001025053
Protein	NP_001020224

Caenorhabditis elegans

mRNA	NM_067320
Protein	NP_499721

Drosophila melanogaster

mRNA	NM_166188
Protein	NP_725602

J. Biol. Chem. 1998-11-01 ;273(46):30472-81.

Cloning of a human UDP-N-acetyl-alpha-D-Galactosamine:polypeptide N-acetylgalactosaminyltransferase that complements other GalNAc-transferases in complete O-glycosylation of the MUC1 tandem repeat.

Bennett EP. et al. PMID:9804815

DONOR : UDP-GalNAc

Glc	Man	Gal	GlcNAc	GalNAc	Fuc	Xyl	Neu5Ac	Neu5Gc	GlcA	IdoA	GlcN

Substrate Transferred

	HO-Ser/Thr (Glycopeptide)	UDP-GalNAc	GalNAc(alpha1-O)-Ser/Thr (Glycopeptide)

Table III Substrate spesificities of purified recombinant GalNAc-T4 and -T2
Peptide (sequence)	activity (at 0.25 mM) (milliunits/mg)
Muc7 (CPPTPSATTPAPPSSSAPPETTAA)	53.0
EA2 (DSTTPAPTTK)	42.0
Muc2 (PTTTPISTTTMVTPTPTPTC)	29.0
GalNAc4 TAP24 (TAPPAHGVTSAPDTRPAPGSTAPP)	7.1
TAP24 (TAPPAHGVTSAPDTRPAPGSTAPP)	2.7
Muc1a' (AHGVTSAPDTR)	2.0
PSGL-1b (Ac-QATEYEYLDYDFLPETEPPEM)	1.4
Muc1b' (RPAPGSTAPPA)	0.7

table 4 Kinetic constants of purified recombinant GalNAc-transferases
Substrate (sequence)	Vmax (nmol/min/mg)
EA2 peptide (DSTTPAPTTK)	0.4400
Muc7 peptide (CPPTPSATTPAPPSSSAPPETTAA)	0.2500
GalNAc4TAP24 peptide (TAPPAHGVTSAPDTRPAPGSTAPPd)	0.0070
PSGL-1b peptide (Ac-QATEYEYLDYDFLPETEPPEM)	0.0030

RNA Expression from Human Protein Atlas

This RNA expression data uses "HPA data" from the Human Protein Atlas. Tissue RNA Expression

data available from v22.proteinatlas.org

J. Biol. Chem. 1998-11-01 ;273(46):30472-81.

Cloning of a human UDP-N-acetyl-alpha-D-Galactosamine:polypeptide N-acetylgalactosaminyltransferase that complements other GalNAc-transferases in complete O-glycosylation of the MUC1 tandem repeat.

Bennett EP. et al. PMID:9804815

adrenal cortexadrenal medullaappendixbone marrowcolonfetal liverkidneyliverlymph nodeovarypancreasperipheral blood leukocytesmall intestinespleenstomachtestisthymusthyroid gland

Provided by GOA

Function
carbohydrate binding
metal ion binding
polypeptide N-acetylgalactosaminyltransferase activity

Process
O-glycan processing
carbohydrate metabolic process

Component
Golgi apparatus
Golgi membrane
extracellular exosome
integral component of membrane
perinuclear region of cytoplasm

GALNT4

UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase

Orthologous Gene

Mus musculus

Rattus norvegicus

Caenorhabditis elegans

Drosophila melanogaster

Acceptor Substrates (Reference)

Cloning of a human UDP-N-acetyl-alpha-D-Galactosamine:polypeptide N-acetylgalactosaminyltransferase that complements other GalNAc-transferases in complete O-glycosylation of the MUC1 tandem repeat.

DONOR : UDP-GalNAc

Substrate Transferred

Acceptor Substrates (KEM-C)

Expression

Expression (Reference)

Cloning of a human UDP-N-acetyl-alpha-D-Galactosamine:polypeptide N-acetylgalactosaminyltransferase that complements other GalNAc-transferases in complete O-glycosylation of the MUC1 tandem repeat.

Gene Ontology