O43451 (MGA_HUMAN) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Maltase-glucoamylase, intestinal

Including the following 2 domains:

1. Maltase
   EC=3.2.1.20
   Alternative name(s):
   Alpha-glucosidase
2. Glucoamylase
   EC=3.2.1.3
   Alternative name(s):
   Glucan 1,4-alpha-glucosidase

Gene names

Name:	MGAM
Synonyms:	MGA, MGAML

Organism

Homo sapiens (Human)

Taxonomic identifier

9606 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Primates › Haplorrhini › Catarrhini › Hominidae › Homo

Protein attributes

Sequence length	1857 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	May serve as an alternate pathway for starch digestion when luminal alpha-amylase activity is reduced because of immaturity or malnutrition. May play a unique role in the digestion of malted dietary oligosaccharides used in food manufacturing.
Catalytic activity	Hydrolysis of terminal, non-reducing (1->4)-linked alpha-D-glucose residues with release of alpha-D-glucose. Hydrolysis of terminal (1->4)-linked alpha-D-glucose residues successively from non-reducing ends of the chains with release of beta-D-glucose.
Subunit structure	Monomer.
Subcellular location	Apical cell membrane; Single-pass type II membrane protein. Note: Brush border.
Tissue specificity	Expressed in small intestine, granulocyte, and kidney but not in salivary gland or pancreas.
Post-translational modification	N- and O-glycosylated. Ref.7 Does not undergo intracellular or extracellular proteolytic cleavage. Sulfated By similarity.
Sequence similarities	Belongs to the glycosyl hydrolase 31 family. Contains 2 P-type (trefoil) domains.

Ontologies

Keywords
Cellular component	Cell membrane Membrane
Coding sequence diversity	Polymorphism
Domain	Repeat Signal-anchor Transmembrane Transmembrane helix
Molecular function	Glycosidase Hydrolase
PTM	Disulfide bond Glycoprotein Sulfation
Technical term	3D-structure Complete proteome Direct protein sequencing Multifunctional enzyme Reference proteome
Gene Ontology (GO)
Biological process	polysaccharide digestion Traceable author statement. Source: Reactome starch catabolic process Traceable author statement. Source: ProtInc
Cellular component	apical plasma membrane Inferred from electronic annotation. Source: UniProtKB-SubCell integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	carbohydrate binding Inferred from electronic annotation. Source: InterPro glucan 1,4-alpha-glucosidase activity Inferred from electronic annotation. Source: EC maltose alpha-glucosidase activity Inferred from electronic annotation. Source: EC
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Initiator methionine

1

1

Removed

Chain

2 – 1857

1856

Maltase-glucoamylase, intestinal

PRO_0000185363

Regions

Topological domain

2 – 13

12

Cytoplasmic Potential

Transmembrane

14 – 34

21

Helical; Signal-anchor for type II membrane protein; Potential

Topological domain

35 – 1857

1823

Lumenal Potential

Domain

88 – 134

47

P-type 1

Domain

954 – 1000

47

P-type 2

Region

198 – 915

718

Maltase

Region

1067 – 1813

747

Glucoamylase

Compositional bias

38 – 84

47

Ser/Thr-rich

Sites

Active site

529

1

Nucleophile By similarity

Active site

532

1

By similarity

Active site

1420

1

Nucleophile By similarity

Active site

1423

1

By similarity

Active site

1526

1

Proton donor By similarity

Amino acid modifications

Modified residue

416

1

Sulfotyrosine Potential

Modified residue

425

1

Sulfotyrosine Potential

Modified residue

1282

1

Sulfotyrosine Potential

Glycosylation

135

1

N-linked (GlcNAc...) Potential

Glycosylation

295

1

N-linked (GlcNAc...)

Glycosylation

457

1

N-linked (GlcNAc...) Potential

Glycosylation

458

1

N-linked (GlcNAc...) Potential

Glycosylation

479

1

N-linked (GlcNAc...)

Glycosylation

707

1

N-linked (GlcNAc...) Potential

Glycosylation

749

1

N-linked (GlcNAc...) Potential

Glycosylation

827

1

N-linked (GlcNAc...)

Glycosylation

885

1

N-linked (GlcNAc...) Potential

Glycosylation

912

1

N-linked (GlcNAc...) Potential

Glycosylation

977

1

N-linked (GlcNAc...) Potential

Glycosylation

989

1

N-linked (GlcNAc...) Potential

Glycosylation

1255

1

N-linked (GlcNAc...) Potential

Glycosylation

1323

1

N-linked (GlcNAc...) Potential

Glycosylation

1364

1

N-linked (GlcNAc...) Potential

Glycosylation

1388

1

N-linked (GlcNAc...) Potential

Glycosylation

1603

1

N-linked (GlcNAc...) Potential

Glycosylation

1672

1

N-linked (GlcNAc...) Potential

Glycosylation

1842

1

N-linked (GlcNAc...) Potential

Glycosylation

1847

1

N-linked (GlcNAc...) Potential

Disulfide bond

90 ↔ 118

By similarity

Disulfide bond

101 ↔ 117

Ref.7

Disulfide bond

112 ↔ 130

Ref.7

Disulfide bond

659 ↔ 670

Ref.7

Disulfide bond

966 ↔ 983

By similarity

Disulfide bond

978 ↔ 996

By similarity

Natural variations

Natural variant

404

1

Q → H.
Corresponds to variant rs2272330 [ dbSNP | Ensembl ].

VAR_047350

Natural variant

542

1

S → L.
Corresponds to variant rs10266732 [ dbSNP | Ensembl ].

VAR_047351

Natural variant

858

1

N → D. Ref.1 Ref.4
Corresponds to variant rs2960746 [ dbSNP | Ensembl ].

VAR_047352

Natural variant

1638

1

L → I.
Corresponds to variant rs9655651 [ dbSNP | Ensembl ].

VAR_047353

Experimental info

Sequence conflict

854

1

L → P in AAI20873. Ref.4

Secondary structure

1

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1857

Helix Strand Turn

Details...

Helix

95 – 97

3

Beta strand

104 – 106

3

Helix

109 – 115

7

Beta strand

129 – 131

3

Beta strand

137 – 140

4

Beta strand

148 – 157

10

Beta strand

163 – 165

3

Beta strand

169 – 179

11

Beta strand

182 – 192

11

Beta strand

214 – 220

7

Turn

221 – 224

4

Beta strand

225 – 230

6

Turn

231 – 233

3

Beta strand

236 – 239

4

Helix

240 – 242

3

Beta strand

246 – 248

3

Beta strand

251 – 257

7

Beta strand

263 – 269

7

Beta strand

272 – 275

4

Beta strand

279 – 285

7

Beta strand

303 – 309

7

Beta strand

316 – 321

6

Beta strand

327 – 332

6

Turn

333 – 335

3

Beta strand

336 – 344

9

Beta strand

346 – 355

10

Helix

356 – 367

12

Helix

375 – 378

4

Beta strand

379 – 382

4

Helix

390 – 402

13

Beta strand

409 – 412

4

Helix

414 – 416

3

Beta strand

417 – 420

4

Turn

427 – 432

6

Helix

433 – 442

10

Beta strand

446 – 451

6

Beta strand

461 – 463

3

Helix

466 – 474

9

Beta strand

483 – 486

4

Beta strand

489 – 491

3

Beta strand

494 – 497

4

Helix

504 – 520

17

Beta strand

524 – 528

5

Turn

531 – 533

3

Beta strand

536 – 540

5

Turn

548 – 550

3

Turn

563 – 566

4

Helix

579 – 582

4

Helix

583 – 585

3

Helix

586 – 601

16

Beta strand

609 – 613

5

Helix

618 – 620

3

Beta strand

623 – 625

3

Beta strand

630 – 632

3

Helix

633 – 648

16

Beta strand

653 – 655

3

Beta strand

661 – 663

3

Helix

667 – 677

11

Beta strand

680 – 685

6

Helix

696 – 699

4

Helix

704 – 718

15

Helix

720 – 732

13

Beta strand

737 – 739

3

Helix

741 – 745

5

Helix

749 – 751

3

Beta strand

758 – 760

3

Turn

761 – 763

3

Beta strand

764 – 767

4

Beta strand

775 – 781

7

Beta strand

786 – 788

3

Turn

789 – 791

3

Beta strand

799 – 805

7

Beta strand

812 – 816

5

Beta strand

819 – 824

6

Helix

830 – 833

4

Beta strand

838 – 843

6

Beta strand

848 – 856

9

Beta strand

859 – 861

3

Turn

862 – 868

7

Beta strand

871 – 889

19

Beta strand

898 – 906

9

Beta strand

911 – 917

7

Beta strand

927 – 931

5

Turn

932 – 935

4

Beta strand

936 – 941

6

Sequences

	Sequence		Length	Mass (Da)
	O43451 [UniParc]. Last modified November 25, 2008. Version 5. Checksum: 166EEC045C2031F7	FASTA	1,857	209,852
	10 20 30 40 50 60 MARKKLKKFT TLEIVLSVLL LVLFIISIVL IVLLAKESLK STAPDPGTTG TPDPGTTGTP 70 80 90 100 110 120 DPGTTGTTHA RTTGPPDPGT TGTTPVSAEC PVVNELERIN CIPDQPPTKA TCDQRGCCWN 130 140 150 160 170 180 PQGAVSVPWC YYSKNHSYHV EGNLVNTNAG FTARLKNLPS SPVFGSNVDN VLLTAEYQTS 190 200 210 220 230 240 NRFHFKLTDQ TNNRFEVPHE HVQSFSGNAA ASLTYQVEIS RQPFSIKVTR RSNNRVLFDS 250 260 270 280 290 300 SIGPLLFADQ FLQLSTRLPS TNVYGLGEHV HQQYRHDMNW KTWPIFNRDT TPNGNGTNLY 310 320 330 340 350 360 GAQTFFLCLE DASGLSFGVF LMNSNAMEVV LQPAPAITYR TIGGILDFYV FLGNTPEQVV 370 380 390 400 410 420 QEYLELIGRP ALPSYWALGF HLSRYEYGTL DNMREVVERN RAAQLPYDVQ HADIDYMDER 430 440 450 460 470 480 RDFTYDSVDF KGFPEFVNEL HNNGQKLVII VDPAISNNSS SSKPYGPYDR GSDMKIWVNS 490 500 510 520 530 540 SDGVTPLIGE VWPGQTVFPD YTNPNCAVWW TKEFELFHNQ VEFDGIWIDM NEVSNFVDGS 550 560 570 580 590 600 VSGCSTNNLN NPPFTPRILD GYLFCKTLCM DAVQHWGKQY DIHNLYGYSM AVATAEAAKT 610 620 630 640 650 660 VFPNKRSFIL TRSTFAGSGK FAAHWLGDNT ATWDDLRWSI PGVLEFNLFG IPMVGPDICG 670 680 690 700 710 720 FALDTPEELC RRWMQLGAFY PFSRNHNGQG YKDQDPASFG ADSLLLNSSR HYLNIRYTLL 730 740 750 760 770 780 PYLYTLFFRA HSRGDTVARP LLHEFYEDNS TWDVHQQFLW GPGLLITPVL DEGAEKVMAY 790 800 810 820 830 840 VPDAVWYDYE TGSQVRWRKQ KVEMELPGDK IGLHLRGGYI FPTQQPNTTT LASRKNPLGL 850 860 870 880 890 900 IIALDENKEA KGELFWDNGE TKDTVANKVY LLCEFSVTQN RLEVNISQST YKDPNNLAFN 910 920 930 940 950 960 EIKILGTEEP SNVTVKHNGV PSQTSPTVTY DSNLKVAIIT DIDLLLGEAY TVEWSIKIRD 970 980 990 1000 1010 1020 EEKIDCYPDE NGASAENCTA RGCIWEASNS SGVPFCYFVN DLYSVSDVQY NSHGATADIS 1030 1040 1050 1060 1070 1080 LKSSVYANAF PSTPVNPLRL DVTYHKNEML QFKIYDPNKN RYEVPVPLNI PSMPSSTPEG 1090 1100 1110 1120 1130 1140 QLYDVLIKKN PFGIEIRRKS TGTIIWDSQL LGFTFSDMFI RISTRLPSKY LYGFGETEHR 1150 1160 1170 1180 1190 1200 SYRRDLEWHT WGMFSRDQPP GYKKNSYGVH PYYMGLEEDG SAHGVLLLNS NAMDVTFQPL 1210 1220 1230 1240 1250 1260 PALTYRTTGG VLDFYVFLGP TPELVTQQYT ELIGRPVMVP YWSLGFQLCR YGYQNDSEIA 1270 1280 1290 1300 1310 1320 SLYDEMVAAQ IPYDVQYSDI DYMERQLDFT LSPKFAGFPA LINRMKADGM RVILILDPAI 1330 1340 1350 1360 1370 1380 SGNETQPYPA FTRGVEDDVF IKYPNDGDIV WGKVWPDFPD VVVNGSLDWD SQVELYRAYV 1390 1400 1410 1420 1430 1440 AFPDFFRNST AKWWKREIEE LYNNPQNPER SLKFDGMWID MNEPSSFVNG AVSPGCRDAS 1450 1460 1470 1480 1490 1500 LNHPPYMPHL ESRDRGLSSK TLCMESQQIL PDGSLVQHYN VHNLYGWSQT RPTYEAVQEV 1510 1520 1530 1540 1550 1560 TGQRGVVITR STFPSSGRWA GHWLGDNTAA WDQLKKSIIG MMEFSLFGIS YTGADICGFF 1570 1580 1590 1600 1610 1620 QDAEYEMCVR WMQLGAFYPF SRNHNTIGTR RQDPVSWDVA FVNISRTVLQ TRYTLLPYLY 1630 1640 1650 1660 1670 1680 TLMHKAHTEG VTVVRPLLHE FVSDQVTWDI DSQFLLGPAF LVSPVLERNA RNVTAYFPRA 1690 1700 1710 1720 1730 1740 RWYDYYTGVD INARGEWKTL PAPLDHINLH VRGGYILPWQ EPALNTHLSR QKFMGFKIAL 1750 1760 1770 1780 1790 1800 DDEGTAGGWL FWDDGQSIDT YGKGLYYLAS FSASQNTMQS HIIFNNYITG TNPLKLGYIE 1810 1820 1830 1840 1850 IWGVGSVPVT SVSISVSGMV ITPSFNNDPT TQVLSIDVTD RNISLHNFTS LTWISTL

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Human small intestinal maltase-glucoamylase cDNA cloning. Homology to sucrase-isomaltase." Nichols B.L., Eldering J.A., Avery S.E., Hahn D., Quaroni A., Sterchi E.E. J. Biol. Chem. 273:3076-3081(1998) [PubMed: 9446624] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], PARTIAL PROTEIN SEQUENCE, VARIANT ASP-858. Tissue: Small intestine.
[2]	Nichols B.L., Eldering J.A., Avery S.E., Hahn D., Quaroni A., Sterchi E.E. Submitted (DEC-2001) to the EMBL/GenBank/DDBJ databases Cited for: SEQUENCE REVISION TO 777; 1050; 1101; 1542; 1613 AND 1812.
[3]	"The DNA sequence of human chromosome 7." Hillier L.W., Fulton R.S., Fulton L.A., Graves T.A., Pepin K.H., Wagner-McPherson C., Layman D., Maas J., Jaeger S., Walker R., Wylie K., Sekhon M., Becker M.C., O'Laughlin M.D., Schaller M.E., Fewell G.A., Delehaunty K.D., Miner T.L. , Nash W.E., Cordes M., Du H., Sun H., Edwards J., Bradshaw-Cordum H., Ali J., Andrews S., Isak A., Vanbrunt A., Nguyen C., Du F., Lamar B., Courtney L., Kalicki J., Ozersky P., Bielicki L., Scott K., Holmes A., Harkins R., Harris A., Strong C.M., Hou S., Tomlinson C., Dauphin-Kohlberg S., Kozlowicz-Reilly A., Leonard S., Rohlfing T., Rock S.M., Tin-Wollam A.-M., Abbott A., Minx P., Maupin R., Strowmatt C., Latreille P., Miller N., Johnson D., Murray J., Woessner J.P., Wendl M.C., Yang S.-P., Schultz B.R., Wallis J.W., Spieth J., Bieri T.A., Nelson J.O., Berkowicz N., Wohldmann P.E., Cook L.L., Hickenbotham M.T., Eldred J., Williams D., Bedell J.A., Mardis E.R., Clifton S.W., Chissoe S.L., Marra M.A., Raymond C., Haugen E., Gillett W., Zhou Y., James R., Phelps K., Iadanoto S., Bubb K., Simms E., Levy R., Clendenning J., Kaul R., Kent W.J., Furey T.S., Baertsch R.A., Brent M.R., Keibler E., Flicek P., Bork P., Suyama M., Bailey J.A., Portnoy M.E., Torrents D., Chinwalla A.T., Gish W.R., Eddy S.R., McPherson J.D., Olson M.V., Eichler E.E., Green E.D., Waterston R.H., Wilson R.K. Nature 424:157-164(2003) [PubMed: 12853948] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
[4]	"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)." The MGC Project Team Genome Res. 14:2121-2127(2004) [PubMed: 15489334] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA], VARIANT ASP-858.
[5]	"Structure, biosynthesis, and glycosylation of human small intestinal maltase-glucoamylase." Naim H.Y., Sterchi E.E., Lentze M.J. J. Biol. Chem. 263:19709-19717(1988) [PubMed: 3143729] [Abstract] Cited for: CHARACTERIZATION. Tissue: Small intestine mucosa.
[6]	"Tyrosine sulfation, a post-translational modification of microvillar enzymes in the small intestinal enterocyte." Danielsen E.M. EMBO J. 6:2891-2896(1987) [PubMed: 3121301] [Abstract] Cited for: SULFATION.
[7]	"Human intestinal maltase-glucoamylase: crystal structure of the N-terminal catalytic subunit and basis of inhibition and substrate specificity." Sim L., Quezada-Calvillo R., Sterchi E.E., Nichols B.L., Rose D.R. J. Mol. Biol. 375:782-792(2008) [PubMed: 18036614] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS) OF 87-954, GLYCOSYLATION, DISULFIDE BONDS.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

AF016833 mRNA. Translation: AAC39568.2.
AC091684 Genomic DNA. Translation: AAP21875.1.
AC073647 Genomic DNA. Translation: AAS07445.1.
AC091742 Genomic DNA. No translation available.
BC120872 mRNA. Translation: AAI20873.1.

IPI

IPI00220143.

RefSeq

NP_004659.2. NM_004668.2.

UniGene

Hs.122785.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
2QLY	X-ray	2.00	A	87-954	[»]
2QMJ	X-ray	1.90	A	87-954	[»]
3CTT	X-ray	2.10	A	87-954	[»]
3L4T	X-ray	1.90	A	87-954	[»]
3L4U	X-ray	1.90	A	87-954	[»]
3L4V	X-ray	2.10	A	87-954	[»]
3L4W	X-ray	2.00	A	87-954	[»]
3L4X	X-ray	1.90	A	87-954	[»]
3L4Y	X-ray	1.80	A	87-954	[»]
3L4Z	X-ray	2.00	A	87-954	[»]
3TON	X-ray	2.95	A/B	960-1853	[»]
3TOP	X-ray	2.88	A/B	960-1853	[»]

ProteinModelPortal

O43451.

SMR

O43451. Positions 93-1001, 1112-1769.

ModBase

Search...

Protein-protein interaction databases

IntAct

O43451. 2 interactions.

STRING

O43451.

Protein family/group databases

CAZy

GH31. Glycoside Hydrolase Family 31.

PTM databases

PhosphoSite

O43451.

Proteomic databases

PRIDE

O43451.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

Ensembl

ENST00000389322; ENSP00000373973; ENSG00000179087.

GeneID

8972.

KEGG

hsa:8972.

UCSC

uc003vwy.1. human.

Organism-specific databases

CTD

8972.

GeneCards

GC07P141607.

H-InvDB

HIX0025263.
HIX0201201.

HGNC

HGNC:7043. MGAM.

HPA

HPA002270.

MIM

154360. gene.

neXtProt

NX_O43451.

PharmGKB

PA30778.

GenAtlas

Search...

Phylogenomic databases

eggNOG

prNOG16500.

HOGENOM

HBG738610.

HOVERGEN

HBG080721.

InParanoid

O43451.

OMA

WAIPGML.

PhylomeDB

O43451.

Enzyme and pathway databases

Reactome

REACT_474. Metabolism of carbohydrates.

Gene expression databases

ArrayExpress

O43451.

Bgee

O43451.

CleanEx

HS_MGA.
HS_MGAM.

Genevestigator

O43451.

Family and domain databases

InterPro

IPR011013. Glyco_hydro-type_carb-bd.
IPR000322. Glyco_hydro_31.
IPR017853. Glycoside_hydrolase_SF.
IPR000519. P_trefoil.
IPR017957. P_trefoil_CS.
[Graphical view]

Gene3D

G3DSA:4.10.110.10. P_trefoil. 2 hits.

KO

K12047.

PANTHER

PTHR22762. Glyco_hydro_31. 1 hit.

Pfam

PF01055. Glyco_hydro_31. 2 hits.
PF00088. Trefoil. 2 hits.
[Graphical view]

SMART

SM00018. PD. 2 hits.
[Graphical view]

SUPFAM

SSF74650. Gal_mut_like. 2 hits.
SSF51445. Glyco_hydro_cat. 2 hits.

PROSITE

PS00129. GLYCOSYL_HYDROL_F31_1. 2 hits.
PS00707. GLYCOSYL_HYDROL_F31_2. 1 hit.
PS00025. P_TREFOIL_1. 1 hit.
PS51448. P_TREFOIL_2. 2 hits.
[Graphical view]

ProtoNet

Search...

Other

DrugBank

DB00284. Acarbose.
DB00491. Miglitol.
DB04878. Voglibose.

NextBio

33667.

SOURCE

Search...

Entry information

Entry name

MGA_HUMAN

Accession

Primary (citable) accession number: O43451
Secondary accession number(s): Q0VAX6, Q75ME7, Q86UM5

Entry history

Integrated into UniProtKB/Swiss-Prot:	May 30, 2000
Last sequence update:	November 25, 2008
Last modified:	January 25, 2012
This is version 111 of the entry and version 5 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.