We reported previously that the incubation of radioiodinated 1-28 human ANP ([I-125]alpha-hANP) for 24 h at 4 degrees C in plasma resulted in a partial conversion to large molecular weight forms of ANP (big ANP) To clarify whether binding of hANP to plasmaproteins is involved, the specificity, sensitivity and saturability of the binding were checked. The results obtained at 4 degrees C do not support the existence of ANP-binding proteins in plasma since none of the predicted requisites was fulfilled. Moreover we checked for temperature dependence of possible specific binding by repeating the same experimental steps at physiological temperature. Although at 37 degrees C there was enhanced binding with respect to that obtained at 4 degrees C, the results further demonstrate that human plasma does not contain specific ANP-binding protein. In conclusion the present data indicate that big ANP is not protein-bound but is an aggregated form. The question remains as to itspossible physiopathological role in vivo.
Big atrial natiuretic peptide: investigation on specific hormone-binding protein
VALACCHI, Giuseppe;
1998
Abstract
We reported previously that the incubation of radioiodinated 1-28 human ANP ([I-125]alpha-hANP) for 24 h at 4 degrees C in plasma resulted in a partial conversion to large molecular weight forms of ANP (big ANP) To clarify whether binding of hANP to plasmaproteins is involved, the specificity, sensitivity and saturability of the binding were checked. The results obtained at 4 degrees C do not support the existence of ANP-binding proteins in plasma since none of the predicted requisites was fulfilled. Moreover we checked for temperature dependence of possible specific binding by repeating the same experimental steps at physiological temperature. Although at 37 degrees C there was enhanced binding with respect to that obtained at 4 degrees C, the results further demonstrate that human plasma does not contain specific ANP-binding protein. In conclusion the present data indicate that big ANP is not protein-bound but is an aggregated form. The question remains as to itspossible physiopathological role in vivo.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
