Activation of chicken liver dihydrofolate reductase by urea and guanidine hydrochloride is accompanied by conformational change at the active site.

Article Details

Citation

Fan YX, Ju M, Zhou JM, Tsou CL

Activation of chicken liver dihydrofolate reductase by urea and guanidine hydrochloride is accompanied by conformational change at the active site.

Biochem J. 1996 Apr 1;315 ( Pt 1):97-102. doi: 10.1042/bj3150097.

PubMed ID
8670138 [ View in PubMed
]
Abstract

It has been reported that the activation of dihydrofolate reductase (DHFR) from L1210 mouse leukaemia cells by KCl or thiol modifiers is accompanied by increased digestibility by proteinases [Duffy, Beckman, Peterson, Vitols and Huennekens (1987) J. Biol. Chem. 262, 7028-7033], suggesting a loosening up of the general compact structure of the enzyme. In the present study, the peptide fragments liberated from the chicken liver enzyme by digestion with trypsin in dilute solutions of urea or guanidine hydrochloride (GuHCl) have been separated by FPLC and sequenced. The sequences obtained are unique when compared with the known sequence of DHFR and thus allow the points of proteolytic cleavage identified for the urea- and GuHCl-activated enzyme to be at or near the active site. It was also indicated by the enhanced fluorescence of 2-p-toluidinylnaphthalene 6-sulfonate that conformational changes at the active site in dilute GuHCl parallel GuHCl activation. The above results indicate that the activation of DHFR in dilute denaturants is accompanied by a loosening up of its compact structure especially at or near the active site, suggesting that the flexibility at its active site is essential for the full expression of its catalytic activity.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
UreaDihydrofolate reductaseProteinGallus gallus
Yes
Activator
Details
Polypeptides
NameUniProt ID
Dihydrofolate reductaseP00378Details