citrate lyase beta subunit-like protein, mitochondrial; citrate lyase beta-like; beta-methylmalate synthase (CLYBL, CLB)

Function

• probably no ATP citrate lyase activity
• mitochondrial malate synthase
• beta-methylmalate synthase
• may play a role in vitamin B12 metabolism

acetyl-CoA + H2O + glyoxylate = (S)-malate + CoA

Propionyl-CoA + H2O + glyoxylate = beta- methylmalate + CoA

Kinetic parameters:

• KM=3.6 mM for glyoxylate (with acetyl-CoA as cosubstrate)
• KM=1.2 mM for glyoxylate (with propionyl-CoA as cosubstrate)
• KM=74 uM for acetyl-CoA
• KM=23 uM for propionyl-CoA
• kcat is 0.12 sec(-1) for malate synthase reaction
• kcat is 0.09 sec(-1) for beta-methylmalate synthase reaction

Cofactor:

• binds 1 Mg+2 per subunit

Structure

• belongs to the hpcH/hpaI aldolase family, citrate lyase beta subunit-like subfamily

Compartment

mitochondria (putative)

Alternative splicing

named isoforms=2

Notes

• humans lack the other subunits necessary for ATP-independent citrate lyase activity
• even though CLYBL resembles citrate lyase beta subunit, it probably has a different enzyme activity

More general terms

• mitochondrial protein
• ATP citrate lyase (citrate cleavage enzyme, ACLY)
• human longevity protein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=171425
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:171425
• OMIM: https://mirror.omim.org/entry/609686
• UniProt: http://www.uniprot.org/uniprot/Q8N0X4.html