Palmitoyl protein hydrolase/thioesterases is an enzyme (EC 3.1.2.22) that removes
thioester-linked fatty acyl groups such as
palmitate from modified cysteine residues in proteins or peptides during
lysosomal degradation. It
catalyzes the reaction
:palmitoyl
rotein+ H
2O
palmitate + protein
This enzyme belongs to the family of
hydrolases, specifically those acting on
thioester bonds. The
systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature.
A semisystematic name or semitrivial ...
is palmitoyl
roteinhydrolase. Other names in common use include palmitoyl-protein thioesterase, and palmitoyl-(protein) hydrolase. This enzyme participates in
fatty acid elongation in mitochondria.
Neuronal ceroid lipofuscinoses
Neuronal ceroid lipofuscinosis is the general name for a family of at least eight genetically separate neurodegenerative lysosomal storage diseases that result from excessive accumulation of lipopigments (lipofuscin) in the body's tissues. These l ...
(NCL) represent a group of encephalopathies that occur in 1 in 12,500 children. Mutations in the palmitoyl protein thioesterase gene causing infantile neuronal ceroid lipofuscinosis.
The most common mutation results in intracellular accumulation of the polypeptide and undetectable enzyme activity in the brain. Direct sequencing of cDNAs derived from brain RNA of INCL patients has shown a mis-sense transversion of A to T at nucleotide position 364, which results in substitution of Trp for Arg at position 122 in the protein - Arg 122 is immediately adjacent to a lipase consensus sequence that contains the putative active site Ser of PPT. The occurrence of this and two other independent mutations in the PPT gene strongly suggests that defects in this gene cause INCL.
Examples
Human proteins containing this domain include:
Structural studies
As of late 2007, 4
structures have been solved for this class of enzymes, with
PDB accession codes , , , and .
See also
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palmitoyl
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Acyl-protein thioesterase
Acyl-protein thioesterases are enzymes that cleave off lipid modifications on proteins, located on the sulfur atom of cysteine residues linked via a thioester bond. Acyl-protein thioesterases are part of the α/β hydrolase superfamily of pr ...
s
References
Further reading
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External links
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GeneReviews/NCBI/NIH/UW entry on Neuronal Ceroid-Lipofuscinoses
EC 3.1.2
Enzymes of known structure
Peripheral membrane proteins
{{3.1-enzyme-stub