dc.contributor.author | Stockman, Paul Kennedy | en |
dc.date.accessioned | 2018-01-31T11:25:08Z | |
dc.date.available | 2018-01-31T11:25:08Z | |
dc.date.issued | 1988 | en |
dc.identifier.uri | http://hdl.handle.net/1842/26977 | |
dc.description.abstract | | en |
dc.description.abstract | A purification scheme is described for the basic and
neutral glutathione S-transferases which occur in human
liver. Three forms with basic isoelectric points,
B-|Bi (pl'8.9), B-|B2 (pi 8.75) and B2B2 (pi 8.4) and two
forms with neutral isoelectric points, N-j (pi 6.1) and
N2 (pi 4.6), were obtained. Not every liver examined
expressed transferase N-] or transferase N2^ An acidic
enzyme from human lung, GST \ (pi 4.8), was included in
the study for the purpose of comparison. | en |
dc.description.abstract | Sodium dodecylsulphate/polyacrylamide-gel electro¬
phoresis demonstrated that each enzyme comprises two subunits
of identical size. As a group the human glutathione
S-transferases are composed of three distinct types of
subunit with different molecular weights. The basic
enzymes (B-]B-j, B1B2 and B2B2) were shown to have a subunit
molecular weight of Mr 25 900, whereas, the neutral enzy¬
mes (N-] and N2) were found to comprise subunits of molecu¬
lar weight Mr 26 500 and the acidic transferase from lung
( X) was shown to be composed of subunits of molecular
weight Mr 24 800. Antisera were raised against each of
these enzymes and they were shown to cross-react only with
enzymes from the same charge/molecular weight group. | en |
dc.description.abstract | Contrary to previous work (Kamisaka e^t_ al_., ( 1975) Eur.
J. Biochem. 60_: 153-161) data are presented to
demonstrate that two distinct basic subunits are
expressed in human liver (B^ and B2). Reversible dissociation and reassociation experiments demonstrated that
transferases B-|Bi and B2B2 could be formed from trans¬
ferase B-1B2. Tryptic-di gest peptide 'maps' showed that
the B-| and B2 subunits possess extensive sequence homo¬
logy, however, seven peptides were recovered from trans¬
ferase B-|Bi that were not recovered from transferase B2B2.
Conversely, four peptides were recovered from transferase
B2B2 that were not recovered from transferase B1B1.
However, all these peptides were recovered from trans¬
ferase B*i B2; this is consistent with the hypothesis that
B1B2 is a hybrid enzyme. | en |
dc.description.abstract | A comparison of the substrate specificities of the
enzymes demonstrated that transferases B -| B1, B-] B2 and
B2B2 had a high peroxidase activity with cumene hydro¬
peroxide, transferases N-| and N2 had a high activity with
trans-4 -phenyl-3 -but en-2- one and transferaseX had a high
activity with ethacrynic acid. The IC50 values obtained
for the basic enzymes demonstrated that the B1 subunit was
much more potently inhibited by tributyltin acetate than
the B2 subunit. | en |
dc.description.abstract | The isoelectric point, molecular weight and high spe¬
cific activity with trans-4-phenyl-3-buten-2-one of trans¬
ferase N-| suggest that it is identical to transferase ]x, a
form that has been previously characterised by Warholm et
al., ( 1983) Biochemistry 22_: 361 0—3617- However, transferanse
N2 is a novel enzyme that has not been described
previously. The properties of this new enzyme indicate
that it also belongs to the neutral group of enzymes. | en |
dc.publisher | The University of Edinburgh | en |
dc.relation.ispartof | Annexe Thesis Digitisation Project 2017 Block 15 | en |
dc.relation.isreferencedby | Already catalogued | en |
dc.title | The glutathione S-transferases in human liver cytosol | en |
dc.type | Thesis or Dissertation | en |
dc.type.qualificationlevel | Doctoral | en |
dc.type.qualificationname | PhD Doctor of Philosophy | en |