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Ca2+-activated protease activity in frog sciatic nerve : Characterization and effect on rapidly transported axonal proteins

Kanje, Martin LU ; Lazarewicz, Jerzy; Ekström, Per LU and Edström, Anders LU (1985) In Brain Research 327(1-2). p.29-36
Abstract

Protease activity was studied in the frog sciatic nerve. The activity was measured as the release of TCA-soluble radioactivity from either 3H-labelled proteins transported by rapid axonal transport (AXT) or 3H-labelled ganglionic proteins. In nerve homogenates containing transported substrates, protease activity exhibited two peaks, one around pH 5 and one around pH 8. Ca2+ at 100 μM or higher concentrations only stimulated the latter, which was inhibited by 1 mM parachloromercuric benzoate, a sulphydryl reagent, but unaffected by ATP (1 mM). The proteolytic activity was recovered in the 105 g supernatant of the homogenate. In desheathed nerves containing 3H-labelled transported... (More)

Protease activity was studied in the frog sciatic nerve. The activity was measured as the release of TCA-soluble radioactivity from either 3H-labelled proteins transported by rapid axonal transport (AXT) or 3H-labelled ganglionic proteins. In nerve homogenates containing transported substrates, protease activity exhibited two peaks, one around pH 5 and one around pH 8. Ca2+ at 100 μM or higher concentrations only stimulated the latter, which was inhibited by 1 mM parachloromercuric benzoate, a sulphydryl reagent, but unaffected by ATP (1 mM). The proteolytic activity was recovered in the 105 g supernatant of the homogenate. In desheathed nerves containing 3H-labelled transported proteins, the protease activity could be activated by exposing the nerve to a Ca2+-ionophore, X-537 A, or to an elevated Ca2+-concentration (50 mM). These conditions were also shown to increase the influx and efflux of 45Ca2+ in the nerves. The results indicate the presence within axons of a Ca2+-activated soluble protease, which degrades rapidly transported proteins. The finding that the protease degraded ganglionic soluble proteins to about the same extent suggests a broad substrate specificity. The present system should be useful for further characterization of protease activity during various physiological conditions.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
axonal transport, Ca, protease activity
in
Brain Research
volume
327
issue
1-2
pages
8 pages
publisher
Elsevier
external identifiers
  • scopus:0021894523
ISSN
0006-8993
DOI
10.1016/0006-8993(85)91495-7
language
English
LU publication?
yes
id
d2c1f272-f2d5-49b7-923f-ccf50ee24954
date added to LUP
2016-12-07 14:26:54
date last changed
2017-06-01 15:59:23
@article{d2c1f272-f2d5-49b7-923f-ccf50ee24954,
  abstract     = {<p>Protease activity was studied in the frog sciatic nerve. The activity was measured as the release of TCA-soluble radioactivity from either <sup>3</sup>H-labelled proteins transported by rapid axonal transport (AXT) or <sup>3</sup>H-labelled ganglionic proteins. In nerve homogenates containing transported substrates, protease activity exhibited two peaks, one around pH 5 and one around pH 8. Ca<sup>2+</sup> at 100 μM or higher concentrations only stimulated the latter, which was inhibited by 1 mM parachloromercuric benzoate, a sulphydryl reagent, but unaffected by ATP (1 mM). The proteolytic activity was recovered in the 10<sup>5</sup> g supernatant of the homogenate. In desheathed nerves containing <sup>3</sup>H-labelled transported proteins, the protease activity could be activated by exposing the nerve to a Ca<sup>2+</sup>-ionophore, X-537 A, or to an elevated Ca<sup>2+</sup>-concentration (50 mM). These conditions were also shown to increase the influx and efflux of <sup>45</sup>Ca<sup>2+</sup> in the nerves. The results indicate the presence within axons of a Ca<sup>2+</sup>-activated soluble protease, which degrades rapidly transported proteins. The finding that the protease degraded ganglionic soluble proteins to about the same extent suggests a broad substrate specificity. The present system should be useful for further characterization of protease activity during various physiological conditions.</p>},
  author       = {Kanje, Martin and Lazarewicz, Jerzy and Ekström, Per and Edström, Anders},
  issn         = {0006-8993},
  keyword      = {axonal transport,Ca,protease activity},
  language     = {eng},
  month        = {02},
  number       = {1-2},
  pages        = {29--36},
  publisher    = {Elsevier},
  series       = {Brain Research},
  title        = {Ca2+-activated protease activity in frog sciatic nerve : Characterization and effect on rapidly transported axonal proteins},
  url          = {http://dx.doi.org/10.1016/0006-8993(85)91495-7},
  volume       = {327},
  year         = {1985},
}