Biomaterial Database

Preparation of 125I-(Tyr 3)- and 125I-(Tyr 11)- neurotensin for radioimmunoassay. 1983

J H Pedersen, and F Stadil, and J Fahrenkrug

The chloramine-T method for radioiodination of neurotensin for radioimmunoassay was studied. As conventional procedures produced heterogeneous preparations, labelling was performed with a low amount of chloramine-T (1.8 nmol) in the presence of excess of peptide (6 nmol). Purification and complete separation of labelled from unlabelled peptide was obtained by ion-exchange chromatography on SP Sephadex C-25. Four labelled components were identified by isoelectric focusing, enzymatic cleavage and studies of immunoreactivity. The two components representing monoiodinated preparations labelled at Tyr 3 or Tyr 11 could be isolated. Depending on the binding site of the particular antiserum the appropriate tracer could be selected for use in the radioimmunoassay. The specific radioactivities were high (2303 (2137-2407) microCi/nmol and 1927 (1608-2307) microCi/nmol (median and range] and the stability of the label and the reproducibility of the procedure was good.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D007553	Isotope Labeling	Techniques for labeling a substance with a stable or radioactive isotope. It is not used for articles involving labeled substances unless the methods of labeling are substantively discussed. Tracers that may be labeled include chemical substances, cells, or microorganisms.	Isotope Labeling, Stable,Isotope-Coded Affinity Tagging,Isotopically-Coded Affinity Tagging,Affinity Tagging, Isotope-Coded,Affinity Tagging, Isotopically-Coded,Isotope Coded Affinity Tagging,Labeling, Isotope,Labeling, Stable Isotope,Stable Isotope Labeling,Tagging, Isotope-Coded Affinity,Tagging, Isotopically-Coded Affinity
D009496	Neurotensin	A biologically active tridecapeptide isolated from the hypothalamus. It has been shown to induce hypotension in the rat, to stimulate contraction of guinea pig ileum and rat uterus, and to cause relaxation of rat duodenum. There is also evidence that it acts as both a peripheral and a central nervous system neurotransmitter.
D011863	Radioimmunoassay	Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.	Radioimmunoassays