ISSN:
1573-6830
Keywords:
squid optic lobe
;
synaptosomes
;
protein phosphorylation
;
4-aminopyridine
;
calcium
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary 1. When intact synaptosomes were incubated with [γ-32P]ATP, maximal protein phosphorylation was attained 2 min after the start of incubation. 2. Protein phosphorylation under basal conditions was dependent on external Ca2+, and the dominant peak of phosphorylation was a 50-kd protein. 3. Incubation of intact synaptosomes in the presence of 3–6 mM 4-aminopyridine (4-AP) caused a markedly enhanced phosphorylation of high molecular weight proteins of 90, 100, 130, and 180 kd, with no increase in the 50 or 38 kd proteins. 4. This effect of 4-AP was dependent on external calcium ions in the incubation medium. 5. The 4-AP effect on the high molecular weight proteins was also found in synaptosomal plasma membranes isolated from the synaptosomes. 6. Tetraethylammonium (TEA) ions did not produce this enhancement of phosphorylation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00710949
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