Preparation and characterization of a biologically active gastrin derivative modified with an /sup 125/I-labeled imidoester

Journal Article · Sat Aug 01 04:00:00 EDT 1981 · Anal. Biochem.; (United States)

DOI:https://doi.org/10.1016/0003-2697(81)90007-5· OSTI ID:5798994

Praissman, M ^[1]; Praissman, L; B H, Kento S; Berkowitz, J M

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1. Nassau County Medical Center, East Meadow, NY

Both trace-labeled and high-specific activity /sup 125/I-labeled derivatives of hexadecapeptide gastrin (G) were prepared by reaction with the iodinated form of the imidoester, methyl p-hydroxybenzimidate. Reaction conditions for preparation of trace-labeled iodinated imidoester gastrin (IIE-G) were: excess imidoester to G (IIe:G, 20:1), pH 9.2, and a reaction time of 24 h. Following purification by gel filtration and silica gel chromatography, an IIE-G component was isolated which appeared homogeneous on thin-layer chromatography and retained the same biological and immunological properties as unmodified G. Somewhat different conditions were necessary to prepare high specific activity iodinated imidoester gastrin (IIE*-G). These included reducing the volume (20 ..mu..l) and pH (7.5) at which the imidoester was iodinated and adjusting the concentrations of reactants to the same molar amounts as 5 mCi of carrier-free /sup 125/I. Sufficient amounts of IIE*-G were obtained by reversing the ratio of G and IIE* and reacting with a G excess (GIIE*, 10:1). The purified IIE*-G had a specific activity exceeding 1500 ..mu..Ci/nmol and was used to establish a specific radioimmunoassay for gastrin.

• OSTI ID: 5798994
• Journal Information: Anal. Biochem.; (United States), Journal Name: Anal. Biochem.; (United States) Vol. 115:2; ISSN ANBCA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BETA DECAY RADIOISOTOPES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
DATA
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EXPERIMENTAL DATA
GASTRIN
HALOGENATION
HORMONES
INFORMATION
INTERMEDIATE MASS NUCLEI
IODINATION
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MEASURING METHODS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PEPTIDES
PHYSICAL PROPERTIES
POLYPEPTIDES
PROTEINS
RADIOASSAY
RADIOIMMUNOASSAY
RADIOISOTOPES
SYNTHESIS
TRACER TECHNIQUES
UPTAKE