Isolation and characterization of chromodulin from chicken liver and related spectroscopic and immunological studies in chromium biochemistry

Bovine chromodulin is a ∼1.5 kDa oligopeptide that binds four chromic ions and potentiates insulin action. 1H NMR and electronic spectroscopic studies indicate that chromodulin contains a multinuclear chromic assembly but provide little information about the arrangement of the chromic ions. Low-temperature X-band EPR studies suggest that bovine chromodulin consists of a trinuclear assembly in close proximity to a mononuclear chromic center.; Chromodulin has been isolated from several mammalian sources, but to date not from a non-mammalian source. With chromodulin's apparent role in potentiating insulin action and the wide range of animals that utilize insulin, other animals could also produce chromodulin. A chromium-containing oligopeptide has been isolated from chicken liver. This oligopeptide has very similar spectroscopic characteristics to those of bovine chromodulin including low temperature X-band EPR features, suggesting that the chicken oligopeptide possesses a similar arrangement of chromic ions to that of bovine chromodulin.; Tracking the fate of chromodulin and a synthetic analogue of chromodulin in the body is difficult. Attempts to generate antibodies to these compounds, including using a segment of the protein ADAM 19, to develop specific probes for the compounds are described. The synthetic fragment of ADAM 19 was found to share several properties with chromodulin and could serve as a model to study the binding of chromic ions to chromodulin.; The carcinogenetic action of chromate has been shown to involve the formation of Cr(III)-DNA species. Studies have shown that the preferred binding sites on the DNA backbone involve guanine residues; unfortunately, these sites are difficult to probe spectroscopically. The use of 1H NMR as a probe to obtain more detailed structural information was tested using a series of model chromium(III) compounds; unfortunately, 1H NMR was found to be of limited utility due to the paramagnetic nature of the chromic ions.