Comparison of L-aspartate 4-carboxy-lyases of Cunninghamella elegans and Penicillium citrinum.
L-Aspartate 4-carboxy-lyase of Cunninghamella elegans and Penicillium citrinum has a pH optimum of 5.5. Maximal activity of both enzymes is obtained at 40 degrees C, and both are thermolabile. The Km of the C. elegans enzyme for L-aspartate is 25 mM, while that of the P. citrinum enzyme is 27 mM. The two enzymes are specific for L-aspartate. They are activated by pyridoxal 5-phosphate and a number of alpha-keto acids. The catalytic activity of both enzymes is stimulated by Co2+, Fe2+, Ni2+ and Mn2+ ions and inhibited by Zn2+ and Cu2+. Inhibition by iodoacetate and activation by SH-compounds suggest that sulfhydryl groups may participate in enzyme activity.
el-Rahmany
T A
TA
Faculty of Science (Girls), Al-Azhar University, Cairo, Egypt.
D000409:Alanine / Q000096:biosynthesis; D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003653:Decarboxylation / Q000187:drug effects; D004492:Edetic Acid / Q000494:pharmacology; D004789:Enzyme Activation; D005978:Glutathione / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D007651:Keto Acids / Q000494:pharmacology; D007700:Kinetics; D008623:Mercaptoethanol / Q000494:pharmacology; D008670:Metals / Q000494:pharmacology; D009090:Mucorales / Q000201:enzymology*; D010407:Penicillium / Q000201:enzymology*; D011732:Pyridoxal Phosphate / Q000494:pharmacology; D013696:Temperature
D007461:Iodoacetates; D007651:Keto Acids; D008670:Metals; D011732:Pyridoxal Phosphate; D008623:Mercaptoethanol; D004492:Edetic Acid; D002262:Carboxy-Lyases; C019747:aspartate 4-decarboxylase; D005978:Glutathione; D000409:Alanine; D019807:Iodoacetic Acid