Relationship between the multiple forms of rat gastric histidine decarboxylase: effects of conditions favouring phosphorylation and dephosphorylation.
Conditions favouring protein phosphorylation and dephosphorylation are examined for their effects on activity and charge heterogeneity of the rat gastric mucosal histidine decarboxylase. Incubation of gastric supernatant with various combinations of ATP, Mg2+, cyclic AMP and protein kinase under the blockade of endogenous phosphodiesterase and phosphatase fails to alter significantly enzyme activity as assayed with or without pyridoxal 5'-phosphate. Similar results are found with the purified enzyme. No change occurs in the distribution of activity between the charged forms. In contrast, treatment with alkaline phosphatase both inactivates the enzyme with preservation of heterogeneity, full reactivation being achieved by pyridoxal 5'-phosphate, and reduces the number of forms and converts forms II and III to form I with preservation of the catalytic potentialities. The data suggest that the enzyme heterogeneity may be related in part to the phosphorylation state; the possibility that the gastric enzyme is susceptible to several post-translational modifications is discussed.
Savany
A
A
Laboratoire de Chimie Biologique, INSERM U. 205, Institut National des Sciences Appliquées, Villeurbanne, France.
Cronenberger
L
L
D000255:Adenosine Triphosphate / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D005753:Gastric Mucosa / Q000201:enzymology*; D006640:Histidine Decarboxylase / Q000378:metabolism*; D007525:Isoelectric Focusing; D008274:Magnesium / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats
D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D011494:Protein Kinases; D000469:Alkaline Phosphatase; D010744:Phosphoric Monoester Hydrolases; D010727:Phosphoric Diester Hydrolases; D002262:Carboxy-Lyases; D006640:Histidine Decarboxylase; D008274:Magnesium