Determination, Localization and Properties of the Specific Histidine Decarboxylases in the Gastric Mucosa of Man and other Mammals / Nachweis, Lokalisation und Eigenschaften von Histidindecarboxylasen in der Magenschleimhaut des Menschen und verschiedener Säugetiere
In crude extracts (supernatants after ultracentrifugation at 100000 × g) of the gastric mucosa of man and many other mammals, specific histidine decarboxylases could be determined by the method of Lorenz et al. [2, 3]. The activities of these enzymes, expressed as mean values of several determinations in pMol histamine formation/min and mg biuret protein, were relatively high in the fundus and corpus of the stomach: man 10.6 and 7.1; shimpanzee 18.7 and 4.6; dog 38.4 and 46.5; pig 202 and 60; cow in the corpus 44.7; cat in the fundus 7.4; rabbit 15.2 and 5.1; guinea-pig 16.4 and 13.8; rat in the whole glandular portion of the stomach 29.3. The specific histidine decarboxylases were characterized by pH-optimum, K m , inhibition by α-methylhistidine and benzene, but not by α-methyldopa and activation by pyridoxal-5′ phosphate (tab.). The enzyme of the gastric mucosa of guinea-pigs was purified 22-fold by ultracentrifugation and gelfiltration on Sephadex G 100. The demonstration of the specific histidine decarboxylase in the gastric mucosa of many mammilian species besides other criteria supports the hypothesis of a physiological role of histamine as chemostimulator of the gastric secretion.
- 2.Lorenz, W., St. Halbach, M. Gerant, and E. Werle: Biochem. Pharmacol. (in press).Google Scholar