Linked Life Data

10801859

Source:http://linkedlifedata.com/resource/pubmed/id/10801859

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
31
pubmed:dateCreated
2000-9-7
pubmed:databankReference
pubmed:abstractText
Palmitoyl-protein thioesterase-1 (PPT1) is a newly described lysosomal enzyme that hydrolyzes long chain fatty acids from lipid-modified cysteine residues in proteins. Deficiency in this enzyme results in a severe neurodegenerative storage disorder, infantile neuronal ceroid lipofuscinosis. Although the primary structure of PPT1 contains a serine lipase consensus sequence, the enzyme is insensitive to commonly used serine-modifying reagents phenylmethylsulfonyl fluoride (PMSF) and diisopropylfluorophosphate. In the current paper, we show that the active site serine in PPT1 is modified by a substrate analog of PMSF, hexadecylsulfonylfluoride (HDSF) in a specific and site-directed manner. The apparent K(i) of the inhibition was 125 micrometer (in the presence of 1.5 mm Triton X-100), and the catalytic rate constant for sulfonylation (k(2)) was 3.3/min, a value similar to previously described sulfonylation reactions. PPT1 was crystallized after inactivation with HDSF, and the structure of the inactive form was determined to 2.4 A resolution. The hexadecylsulfonyl was found to modify serine 115 and to snake through a narrow hydrophobic channel that would not accommodate an aromatic sulfonyl fluoride. Therefore, the geometry of the active site accounts for the reactivity of PPT1 with HDSF but not PMSF. These observations suggest a structural explanation as to why certain serine lipases are resistant to modification by commonly used serine-modifying reagents.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
23847-51
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Structural basis for the insensitivity of a serine enzyme (palmitoyl-protein thioesterase) to phenylmethylsulfonyl fluoride.
pubmed:affiliation
Department of Internal Medicine and the Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8593, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't