title: Effects of EGTA and calmodulin, neutral thiol proteinases and protein kinase C inhibitors on loss of chicken pineal serotonin N-acetyltransferase activity.
abstract: 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.
authors.affiliation: Departamento de Bioquimica, Facultad de Ciencias, Universidad de Valladolid, Spain.
authors.forename: J C
authors.initials: JC
authors.lastname: Rodriguez-Cabello
authors.forename: M T
authors.initials: MT
authors.lastname: Agapito
authors.forename: I
authors.initials: I
authors.lastname: Garcia-Herrero
authors.forename: J M
authors.initials: JM
authors.lastname: Recio
mesh_terms: 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
chemical_list: 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