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Amidating processing enzyme complex for bioactive peptides (PAM) shows differences in specific activity and form in secretory granules isolated from the proximal and distal parts of the hypothalamo‐neurohypophyseal tract in rats
Author(s) -
Hu H.-M.,
Thorn N.A.
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80145-k
Subject(s) - granule (geology) , enzyme , hypothalamus , chemistry , blot , western blot , biochemistry , specific activity , medicine , endocrinology , biology , paleontology , gene
In rats the PAM specific activity in hypothalamic and neurohypophyseal extracts was 0.58 ± 0.8, respectively 1.78 ± 0.6 nmol · mg prot. −1 · h −1 ( n = 5). PHM specific activity in the soluble part of the granules was higher in the neurohypophyseal than in the hypothalamic granules, and the fraction of total PHM and PAL present in the soluble part increased with the distance from the hypothalamus from some 45% to approx. 85%. Western blots of membrane and soluble granule fractions showed prevalence of higher mol. wt. forms in hypothalamic granules. It would appear that higher mol. wt. forms of PAM are processed by proteolytic enzymes during transport in the neuron and that non‐neural cells in the neurohypophysis have a considerable PAM activity.