Functional abnormality of proalbumin christchurch

Abstract

Proalbumin Christchurch is a variant of human albumin in which the C-terminal basic residue of the propeptide has undergone a mutation to glutamine. In this investigation spectral and equilibrium dialysis studies have shown that the variant lacks the high affinity copper binding site of normal albumin. A simple electrophoretic procedure is described using 63Ni(II), which allows discrimination of proalbumins from other variants of albumin. The finding that Proalbumin Christchurch is readily cleaved in vitro by trypsin but is secreted uncleaved in vivo is evidence that propeptide cleavage is due to specific proteolysis with paired basic residues being a pre-requisite.