References
tification
of /3-hydroxyisovaleric
acid in the
urine of a patient with isovaleric acidemia.
Biochim Biophys Acts 152, 638-641 (1968).
3. Baerlocher K. 13-Methylcrotonyl-CoA
carboxylase deficiency. In Inborn Errors of
Metabolism,
FA Hommes, CJ Van Den
Berg, Eds., Academic Press,New York, NY,
1973, pp 334-335.
4. Truscott RJW, Malegan D, McCairns E,
et al. New metabolites in isovaleric acidemia. Clin Chim Acta 110, 187-203 (1981).
5. Lehnert W. 3-Hydroxyisoheptanoic acid:
A new metabolite in isovaleric acidemia.
Clin C/rim Acta 113, 101-103 (1981).
6. Lehnert W. Excretion of N-isovalerylglutaniic acid in isovaleric acidemia. Clin
Chim Acta 116, 249-252 (1981).
7. Tanaka K. Disorders of organic acid metabolism. In Biology ofBrain Dysfunction,
GE Gaull, Ed., Plenum Publ. Corp., New
York, NY, 1975, p 155.
8. Schlenk H, Gellerman JL. Esterification
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S. J. Wysocki
Endocrine
and chlorophyll
can be useful alternatives
compounds
to the fiuorescent
probes
now
being
used for
fluoroimmunoassay
testing. The advantage ofporphyrins and chlorophylls
is the large difference in excitation and
porphyrin
1. Tanaka K, Isselbacher KJ. The isolation
and identification of N-isovalerylglycine
from urine of patients with isovaleric acidemia. J Biol Chem 242, 2966-2972 (1967).
2. Tanaka K, Orr JC, Isselbacher KJ. Iden-
Res. Lab.
emission
wavelengths
(Stokes’
shift).
Many of these compounds have excitation wavelengths in the near ultraviolet to visible blue and fluorescence
emission
wavelengths
red to near infra-red.
in the
visible
Table 1 compares
References
Table I Comparison of
Excitation and Emission
Wavelengths
-
EmIssIon
max.
Excftatlon
max.
Compound
Coproporphyrin III
Hematoporphyrin IX
Protoporphyrin IX
(Jroporphyrin I
Chlorophyll a
Chlorophyll b
Fluorescein
Rhodamine
Umbelliferone
nm
401 .5
King
Edward
Memorial
Women
Subiaco,
Western Australia
Hosp.
for
6008
Porphyrinsand Chlorophyllsas
Probes for Fluoroimmunoassays
To the Editor:
Preliminary
studies
(1) show that
1. U.S. and foreign patents pending.
2. Fasman GD, Ed., Handbook of Biochemistry and Molecular Biology, HI, 3rd ed.
CRC Press, Cleveland, OH, 1975, pp 268275.
3. Goedheer JC, Visible absorption and fluorescence of chlorophyll and its aggregates
in solution. In The Chiorophylls, LP Vernon, GR Seely, Eds., Academic Press, New
York, NY, 1966, pp
623
147-184.
Kawamura A, Ed. Fluorescent Anthody
Techniques and TheirApplications,
UniverPark Press, Baltimore, MD, 1977, pp
402
619
409
633
406
626
430
669
453
648
490
552
525
577.5
400
450
Wong RC, Bard JF, Carrico Ed, at al.
Substrate labeled fluorescent immunoassay
for phenytoin in human serum. Clin Chem
25, 686-691 (1979).
6. Soini E, Hemmila
I. Fluoroiminunoas-
say: Present status and key problems. Clin
A. Grauaug
Services
says.
excitation
and emission wave-lengths
of some of the more common porphyrins and chlorophylls with that of fluorescein, rhodamine,
and umbelliferone
(2-5).
N. P. French
Dept. ofNewborn
or for derivitization
to antigenic substances in competitive binding assays. For example, the 7-propionic acid group on porphyrins
(or
chlorophylls
after removal of the phytyl or farnesyl chains) can form amides
or esters (7, 8).
In addition to the biochemical significance of porphyrins
and chlorophylls,
these compounds should prove to be
interesting
probes for fluoroimmunoasglobulins
to the large Stokes’ shift, porand chlorophylls are not as
susceptible
to auto-fluorescing
substances in serum or to interference
caused by light scattering as is the case
with fluorescent probes having Stokes’
shifts of less than 50 nm (6).
Most of the porphyrins
and chlorophylls have side chains that are conveOwing
phyrins
nient
for formation
with
functional
of covalent
bonds
groups on immuno-
Chem 25, 353-361 (1979).
7. Fuhrop J-H, Smith KM. Laboratory
methods. In Porphyrins and Metalloporphyrins, KM Smith, Ed., Elsevier Sci. Pub. Co.,
New York, NY, 1976, pp 826-827.
8. Seely GR. Structure and chemistry of’
functional groups. In The Chiorophylls, LP
Vernon, GR Seely, Eds., Academic Press,
New York, NY, 1966, pp 79-80.
John L. Hendrix
4962 Lakeland Drive
Marietta, GA 30067
CLINICAL CHEMISTRY, Vol. 29, No. 5, 1983
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