P. Lovisetti-scamihorn et al., Pig splenic nerve: peptides derived from chromogranins by proteolytic processing during axonal transport, REGUL PEPT, 79(1), 1999, pp. 63-67
We have investigated the proteolytic processing of chromogranin A, chromogr
anin B and NESP55 (a novel chromogranin-like protein) during axonal transpo
rt using pig splenic nerve as a model. We have also studied the presence of
chromogranin-derived peptides in the perfusate during electrical stimulati
on of this nerve. High-performance gel filtration chromatography followed b
y radioimmunoassay (RLA) revealed that chromogranins are proteolytically pr
ocessed to varying degrees during axonal transport. For chromogranin A and
NESP55, the precursor is still present in the proximal part of the nerve, w
hereas in the distal part and nerve terminals, intermediate-sized peptides
and the free peptides GE-25 and GAIPLRRH dominate, respectively. For chromo
granin B, the precursor has already been processed to an intermediate-sized
peptide in the proximal part of the nerve, which is also present in the di
stal parts together with the free peptide PE-11. For chromogranin B and NES
P55, only the free peptides PE-11 and GAIPIRRH, or in the case of chromogra
nin A, the free peptide GE-25 plus an intermediate-sized one, are released
from the terminals into the splenic perfusate. These results demonstrate th
at chromogranins are processed to smaller peptides during axonal transport.
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