acetyl-CoA carboxylase 2 (ACC-beta, [includes: biotin carboxylase, ACACB, ACC2, ACCB)

Function

• may be involved in provision of malonyl-CoA or in regulation of fatty acid oxidation, rather than fatty acid biosynthesis
• carries out 3 functions:
  • biotin carboxyl carrier protein
  • biotin carboxylase
  • carboxyltransferase activated by citrate
• inhibited by malonyl-CoA
• long-chain fatty acid biosynthesis; 1st (rate-limiting) step

ATP + acetyl-CoA + HCO3- <--> ADP + phosphate + malonyl-CoA

ATP + biotin-carboxyl-carrier protein + CO2
                   <-->
ADP + phosphate + carboxybiotin-carboxyl-carrier protein

Cofactor:

• biotin (putative)
• binds 2 Mn+2 per subunit (putative)

Kinetic parameters:

• KM=120 uM for ATP
• KM=58 uM for acetyl-CoA
• KM=3.0 mM for NaHCO(3)

Structure

• contains 1 ATP-grasp domain
• contains 1 biotin carboxylation domain
• contains 1 biotinyl-binding domain
• contains 1 carboxyltransferase domain

Compartment

• intracytoplasmic membrane
• may associate with membranes

Alternative splicing

named isoforms=2

Expression

• predominantly expressed in the heart, skeletal muscle & liver

More general terms

• acetyl CoA carboxylase
• phosphoprotein

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:32;
• OMIM: https://mirror.omim.org/entry/601557
• UniProt: http://www.uniprot.org/uniprot/O00763.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=32