section
8.4
Enzymes as Therapeutic Agents
131
H
2
O
2
, A lkaline pH
(HO
2
I
o - c=°
R=protein or peptide or an
organic molecule
Acridinium Ester
10-methy lacridinium
(Electronically excited)
F IG U R E 8 -7
Acridinium ester used as a chemiluminescent tracer. Labeled acridinium ester in the presence of alkaline
hydrogen peroxide undergoes chemical changes producing light that is detected at 430 nm by a photomultiplier
detector.
Solid P h a s e
A ntibody
o
o
o
A n tig en in
S e ru m S a m p le
o_
o_
o_
-C C
_cc
_cc
J
A n tig en L a b e le d w ith
C h em ilu m in e sc e n t
C o m p o u n d (C C )
C C
F IG U R E 8 -8
Competitive binding chemiluminescence assay. The chemiluminescent competitve binding assay is similar to a
RIA. The acridinium ester-labeled substance and the endogenous substance compete with the specific antibody
that is available in limited concentration. The concentration is determined by the quantity of tracer that binds to
the antibody. The use of solid-phase antibody simplifies separation of free from bound tracer.
