Linked Life Data

20667834

Source:http://linkedlifedata.com/resource/pubmed/id/20667834

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
40
pubmed:dateCreated
2010-9-27
pubmed:abstractText
Protein misfolding with loss-of-function of the enzyme phenylalanine hydroxylase (PAH) is the molecular basis of phenylketonuria in many individuals carrying missense mutations in the PAH gene. PAH is complexly regulated by its substrate L-Phenylalanine and its natural cofactor 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (BH(4)). Sapropterin dihydrochloride, the synthetic form of BH(4), was recently approved as the first pharmacological chaperone to correct the loss-of-function phenotype. However, current knowledge about enzyme function and regulation in the therapeutic setting is scarce. This illustrates the need for comprehensive analyses of steady state kinetics and allostery beyond single residual enzyme activity determinations to retrace the structural impact of missense mutations on the phenylalanine hydroxylating system. Current standard PAH activity assays are either indirect (NADH) or discontinuous due to substrate and product separation before detection. We developed an automated fluorescence-based continuous real-time PAH activity assay that proved to be faster and more efficient but as precise and accurate as standard methods. Wild-type PAH kinetic analyses using the new assay revealed cooperativity of activated PAH toward BH(4), a previously unknown finding. Analyses of structurally preactivated variants substantiated BH(4)-dependent cooperativity of the activated enzyme that does not rely on the presence of l-Phenylalanine but is determined by activating conformational rearrangements. These findings may have implications for an individualized therapy, as they support the hypothesis that the patient's metabolic state has a more significant effect on the interplay of the drug and the conformation and function of the target protein than currently appreciated.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
285
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
30686-97
pubmed:dateRevised
2011-10-3
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Activation of phenylalanine hydroxylase induces positive cooperativity toward the natural cofactor.
pubmed:affiliation
Department of Molecular Pediatrics, Dr von Hauner Children's Hospital, Munich 80337, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't