Series of 3-
and 19-oximes of 16
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anoprogesterone deriv
atives (pregn
a-
an class="smCaps">dan>′-pent
ar
anes) h
ave been synthesized with the
aim of probing the surf
aces of progesterone receptor's
and two other protein lig
and binding pockets neighboring to 3-
and 19-positions of steroid core. The s
ame deriv
atives were
also studied
as possible intermedi
ates for
att
achment to m
atrixes. The d
at
a on
affinity const
ants suggest the presence of hydrophobic c
avities with hydrophilic necks in the progesterone receptor
and serum pent
ar
anophylin ne
ar C19 of bound lig
and
and the l
ack of such
a c
avity in uterine pent
ar
anophylin. Any of 3-oxime substitutions were found to signific
antly diminish the lig
and
affinity for the progesterone receptor. It w
as
also found th
at some of these modific
ations, in the
Z-configur
ation p
articul
arly, might incre
ase the
affinity for serum
and uterine pent
ar
anophylins. The l
atter finding suggests the presence of l
arge c
avities ne
ar C3 of bound lig
and in these proteins
and interch
ange
ability between 3-keto
and 3-oxime groups in lig
and–protein inter
actions.