ISSN:
1432-0428
Keywords:
125I-insulin
;
insulin
;
radioiodination
;
iodate
;
lactoperoxidase
;
monoiodotyrosine
;
diiodotyrosine
;
A chain
;
B chain
;
tyrosine-A14
;
tyrosine-A19
;
insulin immunoassay
;
radiochemical purity
;
radioimmunochemical stability
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Mono-125I-(Tyr A19)-insulin (Mono *A19) was prepared by iodinating MC porcine insulin with 125I in acid medium using iodate (as oxidizing agent), followed by anion-exchange chromatography. Mono-125I-(Tyr A14)-insulin (Mono *A14) was prepared by iodinating MC porcine insulin with 125I, using H2O2/lactoperoxidase at neutral pH, followed by anion-exchange chromatography. The specific radioactivities were in the ranges of 120–200 and 220–300 mCi/mg for Mono *A19 and Mono *A14, respectively. Analyses of the intramolecular distributions of 125I demonstrated that the preparations were 97–98% radiochemically pure. In both preparations, 98–99% of the radioactivity was capable of binding to insulin antibodies for up to 6 months of storage of the tracers. The IRI concentration decreased with the duration of storage. The greatest observed fall in IRI concentration was 70%. The time course could be explained by the assumption that the disintegration of a 125I-nucleus destroys the immunoreactivity of the insulin molecule in which the decay occurs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00253183
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