Studies on the three cysteines of mouse glutathione s-transferase P1
Citation:
Gavin McManus, 'Studies on the three cysteines of mouse glutathione s-transferase P1', [thesis], Trinity College (Dublin, Ireland). School of Biochemistry and Immunology, 2006, pp 225Download Item:
Abstract:
The present study has identified the "alkahne thiol" of mGSTP1 originally described by
Phillips and Mantle (1993) as cystein e-169. In addition cysteine-47 is confirmed as the
reactive "neutral" pK thiol. Cysteine-14 in the C14* mutant is unreactive at neutral pH
and only slowly reacts under alkaline conditions. Several key experiments however
suggest that Cys-14 can form a disulphide with Cys-47 and this may occur under
conditions when the basic dimeric structure is maintained. A comparison of the extent of
reaction of DTNB with GSTP1 forms with only Cys-14 or only Cys-47 sum to a
significantly lower value than obtained when both Cys-14 and Cys-47 are present. A
simple mechanism to explain this is has been presented where an initial mixed disulphide
between NTB and Cys-47 destabilises the α2-loop allowing Cys-14 to attack the
modified Cys-47 forming a stable disulphide between Cys-14 and Cys-47 and releasing
NTB. Whether this thioredoxin like half reaction has any functional significance is
presently unclear, how ever it should be noted that treatment of C169A with relatively low
concentrations of H2O2 resulted in the formation of the Cys-14/Cys-47 disulphide as
revealed by a species running with an apparent mobility of 20kDa on SDS/PAGE in the
absence of any mercaptoethanol.
Author: McManus, Gavin
Advisor:
Mantle, TimQualification name:
Doctor of Philosophy (Ph.D.)Publisher:
Trinity College (Dublin, Ireland). School of Biochemistry and ImmunologyNote:
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