EVIDENCE FOR PRESENCE OF PEPTIDE ALPHA-AMIDATING ACTIVITY IN PANCREATIC-ISLETS FROM NEWBORN RATS

被引:7
作者
ZHOU, A [1 ]
THORN, NA [1 ]
机构
[1] UNIV COPENHAGEN,BIOTECHNOL CTR NEUROPEPTIDE RES,DK-2200 COPENHAGEN N,DENMARK
关键词
D O I
10.1042/bj2670253
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The peptide α-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 K(m) of 57 μM, a V(max.) 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 μM 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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页码:253 / 256
页数:4
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