Analysis of Secreted Proteins during Conidial Germination of Aspergillus oryzae RIB40

• Published in: Bioscience, biotechnology, and biochemistry Vol. 68; no. 12; pp. 2607 - 2612
• Main Authors: ZHU, Li Ying, NGUYEN, Cong Ha, SATO, Tsutomu, TAKEUCHI, Michio
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Society for Bioscience, Biotechnology, and Agrochemistry 01.12.2004; Japan Society for Bioscience Biotechnology and Agrochemistry; Oxford University Press
• Subjects: alpha-Amylases - analysis; alpha-Amylases - metabolism; Aspartic Acid Endopeptidases - analysis; Aspartic Acid Endopeptidases - metabolism; aspergillopepsin A; Aspergillus oryzae; Aspergillus oryzae - chemistry; Aspergillus oryzae - growth & development; Biological and medical sciences; conidial germination; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Fungal Proteins - analysis; Fungal Proteins - metabolism; Glucan 1,4-alpha-Glucosidase - analysis; Glucan 1,4-alpha-Glucosidase - metabolism; Hydrogen-Ion Concentration; Peptide Mapping; peptide mass fingerprinting; precursor; Protein Precursors; Protein Processing, Post-Translational; Silver Staining; Peptides; Enzyme; Germination; Precursor; Fungi; aspergillopepsin A; Peptidases; Aspergillus oryzae; Fingerprint method; Secretory protein; peptide mass fingerprinting; Hydrolases; conidial germination; Aspartic endopeptidases; Fungi Imperfecti; Aspergillopepsin I; Thallophyta
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.68.2607

To broaden our understanding of extracellular proteins of Aspergillus oryzae at the conidial germination stage, analyses of the secreted proteins during germination were carried out. Taka-amylase A (TAA), glucoamylase (GLAA), and aspergillopepsin A (PEPA) were identified as the main products by peptide mass fingerprinting. TAA and PEPA were detected simultaneously with the formation of germ tubes. With the development of germination, the pH of the medium fell from 5.5 to 3.5. The secreted PEPA had a pro-sequence and likely shifted from 42 kDa to 41 kDa below pH 4.6, indicating that the precursor of PEPA was secreted and underwent pH-dependent processing. Furthermore, the 41 kDa protein was trapped by the addition of pepstatin A, the specific inhibitor of PEPA, suggesting that the maturation of pro-PEPA was a stepwise autoprocessing upon acidification of the medium and itself was an intermediate of the processing. It was implied that PEPA plays an important role at the early germination stage.