palmitoyl protein thioesterase 2; palmitoyl-protein hydrolase 2 (PPT2, G14)

Function

• removes thioester-linked fatty acyl groups from various substrates including S-palmitoyl-CoA
• highest S-thioesterase activity for the acyl groups palmitic & myristic acid followed by other short- & long-chain acyl substrates
• prefers acyl chain lengths of 14-18 carbons
• however, because of structural constraints, is unable to remove palmitate from peptides or proteins

Kinetic parameters:

• KM=67 uM for S-palmitoyl-CoA
• KM=37 uM for S-palmitoyl-N-acetylcysteamine
• Vmax=1.7 umol/min/mg enzyme toward S-palmitoyl-CoA
• Vmax=3.3 umol/min/mg enzyme toward S-palmitoyl-N-acetyl- cysteamine
• ptimum pH is 7.0

Structure

belongs to the palmitoyl-protein thioesterase family

Compartment

lysosome

Alternative splicing

named isoforms=2

isoform(s) may be catalytically inactive due to lack of His-283, or may be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay

Expression

• broadly expressed, with highest levels in skeletal muscle

More general terms

• thiol esterase or thioesterase
• glycoprotein

Database

• OMIM: https://mirror.omim.org/entry/603298
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=9374
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:9374
• UniProt: http://www.uniprot.org/uniprot/Q9UMR5.html