Reviewed, UniProtKB/Swiss-Prot P43155 (CACP_HUMAN)

Names and origin

Protein names

Recommended name:
    Carnitine O-acetyltransferase
      Short name=Carnitine acetylase
    EC=2.3.1.7
Alternative name(s):
    Carnitine acetyltransferase
      Short name=CrAT
      Short name=CAT

Gene names

Name:	CRAT
Synonyms:	CAT1

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	626 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Carnitine acetylase is specific for short chain fatty acids. Carnitine acetylase seems to affect the flux through the pyruvate dehydrogenase complex. It may be involved as well in the transport of acetyl-CoA into mitochondria.
Catalytic activity	Acetyl-CoA + carnitine = CoA + O-acetylcarnitine.
Subunit structure	Monomer.
Subcellular location	Endoplasmic reticulumPotential. PeroxisomePotential. Mitochondrion inner membrane; Peripheral membrane protein; Matrix sidePotential.
Tissue specificity	Mostly in skeletal muscle, less in heart, liver and pancreas, only weakly detectable in brain, placenta, lung and kidney.
Sequence similarities	Belongs to the carnitine/choline acetyltransferase family.

Ontologies

Keywords
Biological process	Fatty acid metabolism Lipid metabolism Transport
Cellular component	Endoplasmic reticulum Membrane Mitochondrion Mitochondrion inner membrane Peroxisome
Coding sequence diversity	Alternative splicing Polymorphism
Molecular function	Acyltransferase Transferase
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological process	energy derivation by oxidation of organic compounds Ref.5 Traceable author statement. Source: ProtInc fatty acid metabolic process Inferred from electronic annotation. Source: UniProtKB-KW transport Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	endoplasmic reticulum Ref.5 Non-traceable author statement. Source: ProtInc mitochondrial inner membrane Inferred from electronic annotation. Source: UniProtKB-KW peroxisome Ref.5 Non-traceable author statement. Source: ProtInc
Molecular function	carnitine O-acetyltransferase activity Inferred from electronic annotation. Source: EC
Complete GO annotation...

Alternative products

This entry describes 3 isoforms produced by alternative splicing. [Align] [Select]

Isoform 1 (identifier: P43155-1)

Also known as: SM-1400;

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

Notes: May be mitochondrial.

Isoform 2 (identifier: P43155-2)

Also known as: SM-1200;

The sequence of this isoform differs from the canonical sequence as follows:
     1-21: Missing.

Notes: May be peroxisomal. No experimental confirmation available.

Isoform 3 (identifier: P43155-3)

The sequence of this isoform differs from the canonical sequence as follows:
     282-363: Missing.

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 626

626

Carnitine O-acetyltransferase

PRO_0000210172

Regions

Region

418 – 430

13

Coenzyme A binding By similarity

Motif

624 – 626

3

Microbody targeting signal Potential

Sites

Active site

343

1

Proton acceptor Probable

Binding site

452

1

Carnitine

Binding site

454

1

Carnitine

Binding site

465

1

Carnitine

Natural variations

Alternative sequence

1 – 21

21

Missing in isoform 2.

VSP_000792

Alternative sequence

282 – 363

82

Missing in isoform 3.

VSP_012798

Natural variant

372

1

L → M: dbSNP rs3118635.

VAR_047780

Natural variant

624

1

A → P: dbSNP rs17459086.

VAR_047781

Experimental info

Mutagenesis

452

1

Y → A: Increases the KM for carnitine 100-fold

Mutagenesis

452

1

Y → F: Increases the KM for carnitine 320-fold and reduces enzyme activity 10000-fold

Mutagenesis

465

1

T → A: Increases the KM for carnitine almost 70-fold and reduces enzyme activity 450-fold

Mutagenesis

518

1

R → Q: Increases the KM for carnitine 230-fold and reduces enzyme activity almost 100-fold

Mutagenesis

566

1

F → A: Increases the KM for carnitine 18-fold and reduces enzyme activity 100-fold

Mutagenesis

566

1

F → Y: No effect

Sequence conflict

88

1

E → G in CAA55359. Ref.5

Sequence conflict

349

1

P → F in CAA55359. Ref.5

Sequence conflict

517

1

D → G in CAA55359. Ref.5

Sequence conflict

534

1

M → T in CAA55359. Ref.5

Secondary structure

1

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626

Helix Strand Turn

Details...

Helix

43 – 54

12

Turn

55 – 57

3

Helix

60 – 74

15

Helix

79 – 93

15

Beta strand

94 – 96

3

Helix

99 – 106

8

Turn

107 – 109

3

Turn

116 – 118

3

Beta strand

121 – 123

3

Helix

132 – 154

23

Helix

171 – 175

5

Beta strand

179 – 182

4

Beta strand

185 – 187

3

Beta strand

189 – 192

4

Beta strand

196 – 198

3

Beta strand

202 – 207

6

Beta strand

210 – 215

6

Helix

226 – 238

13

Helix

248 – 253

6

Helix

256 – 266

11

Helix

270 – 281

12

Beta strand

285 – 289

5

Helix

300 – 310

11

Turn

314 – 319

6

Beta strand

325 – 332

8

Beta strand

337 – 341

5

Helix

348 – 363

16

Beta strand

379 – 381

3

Helix

387 – 406

20

Beta strand

407 – 414

8

Helix

420 – 424

5

Helix

429 – 445

17

Beta strand

451 – 456

6

Beta strand

465 – 469

5

Helix

473 – 482

10

Helix

489 – 511

23

Helix

517 – 529

13

Helix

536 – 539

4

Helix

541 – 546

6

Beta strand

550 – 555

6

Beta strand

559 – 561

3

Beta strand

563 – 565

3

Beta strand

574 – 580

7

Beta strand

585 – 592

8

Helix

600 – 619

20

Sequences

	Sequence		Length	Mass (Da)
	Isoform 1 (SM-1400) [UniParc]. Last modified November 25, 2008. Version 5. Checksum: 51B65E7C94E458D7	FASTA	626	70,858
	10 20 30 40 50 60 MLAFAARTVV KPLGFLKPFS LMKASSRFKA HQDALPRLPV PPLQQSLDHY LKALQPIVSE 70 80 90 100 110 120 EEWAHTKQLV DEFQASGGVG ERLQKGLERR ARKTENWLSE WWLKTAYLQY RQPVVIYSSP 130 140 150 160 170 180 GVMLPKQDFV DLQGQLRFAA KLIEGVLDFK VMIDNETLPV EYLGGKPLCM NQYYQILSSC 190 200 210 220 230 240 RVPGPKQDTV SNFSKTKKPP THITVVHNYQ FFELDVYHSD GTPLTADQIF VQLEKIWNSS 250 260 270 280 290 300 LQTNKEPVGI LTSNHRNSWA KAYNTLIKDK VNRDSVRSIQ KSIFTVCLDA TMPRVSEDVY 310 320 330 340 350 360 RSHVAGQMLH GGGSRLNSGN RWFDKTLQFI VAEDGSCGLV YEHAAAEGPP IVTLLDYVIE 370 380 390 400 410 420 YTKKPELVRS PLVPLPMPKK LRFNITPEIK SDIEKAKQNL SIMIQDLDIT VMVFHHFGKD 430 440 450 460 470 480 FPKSEKLSPD AFIQMALQLA YYRIYGQACA TYESASLRMF HLGRTDTIRS ASMDSLTFVK 490 500 510 520 530 540 AMDDSSVTEH QKVELLRKAV QAHRGYTDRA IRGEAFDRHL LGLKLQAIED LVSMPDIFMD 550 560 570 580 590 600 TSYAIAMHFH LSTSQVPAKT DCVMFFGPVV PDGYGVCYNP MEAHINFSLS AYNSCAETNA 610 620 ARLAHYLEKA LLDMRALLQS HPRAKL
	Isoform 2 (SM-1200) [UniParc]. Checksum: 915540218D46D9C7		605	68,569
	10 20 30 40 50 60 MKASSRFKAH QDALPRLPVP PLQQSLDHYL KALQPIVSEE EWAHTKQLVD EFQASGGVGE 70 80 90 100 110 120 RLQKGLERRA RKTENWLSEW WLKTAYLQYR QPVVIYSSPG VMLPKQDFVD LQGQLRFAAK 130 140 150 160 170 180 LIEGVLDFKV MIDNETLPVE YLGGKPLCMN QYYQILSSCR VPGPKQDTVS NFSKTKKPPT 190 200 210 220 230 240 HITVVHNYQF FELDVYHSDG TPLTADQIFV QLEKIWNSSL QTNKEPVGIL TSNHRNSWAK 250 260 270 280 290 300 AYNTLIKDKV NRDSVRSIQK SIFTVCLDAT MPRVSEDVYR SHVAGQMLHG GGSRLNSGNR 310 320 330 340 350 360 WFDKTLQFIV AEDGSCGLVY EHAAAEGPPI VTLLDYVIEY TKKPELVRSP LVPLPMPKKL 370 380 390 400 410 420 RFNITPEIKS DIEKAKQNLS IMIQDLDITV MVFHHFGKDF PKSEKLSPDA FIQMALQLAY 430 440 450 460 470 480 YRIYGQACAT YESASLRMFH LGRTDTIRSA SMDSLTFVKA MDDSSVTEHQ KVELLRKAVQ 490 500 510 520 530 540 AHRGYTDRAI RGEAFDRHLL GLKLQAIEDL VSMPDIFMDT SYAIAMHFHL STSQVPAKTD 550 560 570 580 590 600 CVMFFGPVVP DGYGVCYNPM EAHINFSLSA YNSCAETNAA RLAHYLEKAL LDMRALLQSH PRAKL
	Isoform 3 [UniParc]. Checksum: 2AD5B9AA49773E5C		544	61,870
	10 20 30 40 50 60 MLAFAARTVV KPLGFLKPFS LMKASSRFKA HQDALPRLPV PPLQQSLDHY LKALQPIVSE 70 80 90 100 110 120 EEWAHTKQLV DEFQASGGVG ERLQKGLERR ARKTENWLSE WWLKTAYLQY RQPVVIYSSP 130 140 150 160 170 180 GVMLPKQDFV DLQGQLRFAA KLIEGVLDFK VMIDNETLPV EYLGGKPLCM NQYYQILSSC 190 200 210 220 230 240 RVPGPKQDTV SNFSKTKKPP THITVVHNYQ FFELDVYHSD GTPLTADQIF VQLEKIWNSS 250 260 270 280 290 300 LQTNKEPVGI LTSNHRNSWA KAYNTLIKDK VNRDSVRSIQ KKPELVRSPL VPLPMPKKLR 310 320 330 340 350 360 FNITPEIKSD IEKAKQNLSI MIQDLDITVM VFHHFGKDFP KSEKLSPDAF IQMALQLAYY 370 380 390 400 410 420 RIYGQACATY ESASLRMFHL GRTDTIRSAS MDSLTFVKAM DDSSVTEHQK VELLRKAVQA 430 440 450 460 470 480 HRGYTDRAIR GEAFDRHLLG LKLQAIEDLV SMPDIFMDTS YAIAMHFHLS TSQVPAKTDC 490 500 510 520 530 540 VMFFGPVVPD GYGVCYNPME AHINFSLSAY NSCAETNAAR LAHYLEKALL DMRALLQSHP RAKL

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Cloning of human full-length CDSs in BD Creator(TM) system donor vector." Kalnine N., Chen X., Rolfs A., Halleck A., Hines L., Eisenstein S., Koundinya M., Raphael J., Moreira D., Kelley T., LaBaer J., Lin Y., Phelan M., Farmer A. Submitted (MAY-2003) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 3), VARIANT MET-372.
[2]	"DNA sequence and analysis of human chromosome 9." Humphray S.J., Oliver K., Hunt A.R., Plumb R.W., Loveland J.E., Howe K.L., Andrews T.D., Searle S., Hunt S.E., Scott C.E., Jones M.C., Ainscough R., Almeida J.P., Ambrose K.D., Ashwell R.I.S., Babbage A.K., Babbage S., Bagguley C.L. , Bailey J.,