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. 1990 Apr 1;267(1):253-6.
doi: 10.1042/bj2670253.

Evidence for presence of peptide alpha-amidating activity in pancreatic islets from newborn rats

A Zhou  1 , N A Thorn
Affiliations

Evidence for presence of peptide alpha-amidating activity in pancreatic islets from newborn rats

A Zhou et al. Biochem J. .

Abstract

The peptide alpha-amidating activity of a homogenate of pancreatic islets from 5-7-day-old rats was investigated, using as substrate a glycine-extended tripeptide (D-Tyr-Val-Gly). The islet homogenates had a marked amidating activity, with a Km of 57 microM, a Vmax. of 185 pmol/h per mg and a pH optimum of 7.0. This activity was dependent on the presence of ascorbic acid (in the reduced form) and Cu2+, the optimum concentrations being 4 mM and 40 microM respectively. On fractionation of the homogenate, the highest specific activity was found in the soluble fraction. Exocrine pancreatic tissue showed very low levels of amidating activity.

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