Effects of EGTA and calmodulin, neutral thiol proteinases and protein kinase C inhibitors on loss of chicken pineal serotonin N-acetyltransferase activity.
This paper shows that the loss of chicken pineal serotonin N-acetyltransferase activity in crude homogenates of the pineal gland during preincubation at 37 degrees C is a complex process which seems to involve protein kinase C, calmodulin and calcium-activated neutral protease. All three compounds are strongly related to free calcium levels, and hence EGTA effectively prevents this loss of activity. It is proposed that the loss of serotonin N-acetyltransferase activity in crude chicken pineal homogenates is due to a series of molecular events, probably triggered by loss of the calcium gradient present in the intact gland by the homogenization process, leading to rapid serotonin N-acetyltransferase deactivation. In these homogenates two calmodulin inhibitors, a protein kinase C inhibitor and a neutral thiol proteinase inhibitor, and EGTA were found to markedly reduce the rate of serotonin N-acetyltransferase deactivation.
Rodriguez-Cabello
J C
JC
Departamento de Bioquimica, Facultad de Ciencias, Universidad de Valladolid, Spain.
Agapito
M T
MT
Garcia-Herrero
I
I
Recio
J M
JM
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D002147:Calmodulin / Q000494:pharmacology*; D002645:Chickens; D003546:Cysteine Endopeptidases / Q000494:pharmacology*; D015853:Cysteine Proteinase Inhibitors; D004533:Egtazic Acid / Q000494:pharmacology*; D007546:Isoquinolines / Q000494:pharmacology; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D010870:Pineal Gland / Q000201:enzymology*; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D047428:Protein Kinase Inhibitors
D002147:Calmodulin; D015853:Cysteine Proteinase Inhibitors; D007546:Isoquinolines; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D004533:Egtazic Acid; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000123:Acetyltransferases; D001191:Arylamine N-Acetyltransferase; D011493:Protein Kinase C; D003546:Cysteine Endopeptidases; D007930:Leucine; C024974:E 64