The effect of proteinases on phenylalanine ammonia-lyase from the yeast Rhodotorula glutinis.
H J Gilbert, G W Jack
Index: Biochem. J. 199 , 715–723, (1981)
Full Text: HTML
Abstract
Phenylalanine ammonia-lyase (EC 4.3.1.5) of the yeast Rhodotorula glutinis was rapidly inactivated by duodenal juice. It was susceptible to chymotrypsin and subtilisin and to a lesser extent trypsin. Initial proteolysis of the enzyme by chymotrypsin and trypsin resulted in cleavage of the monomeric subunit (75 000 Mr) into a large (65 000 Mr) and a small (10 000 Mr) peptide. The small peptide was rapidly degraded. The 65 000-Mr fragment was resistant to prolonged incubation with chymotrypsin, but was degraded by trypsin under the same conditions. Phenylalanine ammonia-lyase was cleaved into several polypeptides by subtilisin, the 65 000-Mr peptide being totally absent. The N-terminal region of the enzyme was contained in the 65 000-Mr fragment, as was the dehydroalanine moiety, the prosthetic group. Active-site-binding ligands protect the enzyme from inactivation by the three proteinases, and peptide-bond cleavage by trypsin and chymotrypsin. Several chemical modifications were performed on phenylalanine ammonia-lyase. Some decreased its antigenicity, and ethyl acetimidate decreased the rate of degradation of the 65 000-Mr peptide by trypsin. The modification did not protect the enzyme from proteolytic inactivation of the enzymic activity. These observations are discussed in terms of the structure of phenylalanine ammonia-lyase and site of action of the proteinases.
Related Compounds
Related Articles:
The effect of light on gene expression and podophyllotoxin biosynthesis in Linum album cell culture.
2012-07-01
[Plant Physiol. Biochem. 56 , 41-6, (2012)]
2012-12-15
[Food Chem. 135 , 2182-7, (2012)]
Fate of residual lignin during delignification of kraft pulp by trametes versicolor
1998-06-01
[Appl. Environ. Microbiol. 64(6) , 2117-2125, (1998)]
2009-05-01
[Planta 229(6) , 1253-1267, (2009)]