The pho-2A mutant of Neurospora crassa which is deficient in Pi-repressible alkaline phosphatase (EC 3.1.3.1) is also defective in Pi-repressible acid phosphatase (EC 3.1.3.2).
1. The mycelial Pi-repressible acid phosphatase presented p-nitrophenylphosphatase activity with negative cooperativity and Michaelian behavior when synthesized by the wild-type and pho-2A mutant strains of Neurospora crassa, respectively. 2. The major acid phosphatase present in cell extracts of the pho-2A mutant of N. crassa grown in low Pi medium is more thermolabile (t1/2 = 4 min at 54 degrees C, pH 5.4) than that of the wild strain (stable for at least 80 min at 54 degrees C, pH 5.4). 3. The pho-2A mutant of N. crassa secreted a more thermolabile acid phosphatase (t1/2 = 30 min at 50 degrees C, pH 5.4) than the wild strain (t1/2 of at least 80 min at 50 degrees C, pH 5.4). 4. The pho-2A mutant of N. crassa synthesized a more thermolabile acid phosphatase (t1/2 = 37 min at 54 degrees C, pH 5.4) than the wild strain in high Pi medium (t1/2 = 14 min at 54 degrees C, pH 5.4). 5. The pleiotropic nature of the pho-2 locus and its possible involvement in the mechanism of phosphatase secretion by N. crassa are proposed.
Han
S W
SW
Departamento de Bioquímica e Microbiologia, Universidade Estadual Paulista, Rio Claro, Brasil.
Maccheroni
W
W
Rossi
A
A
D009597:4-Nitrophenylphosphatase / Q000378:metabolism; D000135:Acid Phosphatase / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics; D000469:Alkaline Phosphatase / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics; D004794:Enzyme Repression; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D009154:Mutation / Q000502:physiology*; D009491:Neurospora / Q000201:enzymology* / Q000235:genetics; D013696:Temperature
D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D009597:4-Nitrophenylphosphatase