The Proteolytic System of Candida dubliniensis

Abstract

Proteases of Candida dubliniensis have been scarcely studied, these enzymes may play an important role in nitrogen metabolism, post-translational processing, nutritional stress, dimorphism, virulence, etc. In this work, we report the presence of five different intracellular proteases and one extracellular proteolytic activity. The intracellular proteases are: aminopeptidase ycdAPE, carboxypeptidase ycdCP, dipeptidyl aminopeptidase ycdDAP, proteinases ycdPrA and ycdPrB, and extracellular protease Sap activity, measured under several nutritional conditions. C. dubliniensis produced the highest level of intracellular proteolytic enzymes, i.e., ycdAPE, ycdCP, ycdDAP, ycdPrA and ycdPrB in media with peptone during stationary growth phase. Chelating agents affected mainly APE activity; whereas ycdCp, ycdDAP, and ycdPrB were affected by serine protease inhibitors; ycdPrA was affected by pepstatin, an aspartyl protease inhibitor. We found Sap activity in C. dubliniensis in YCB-SBA medium, this activity was inhibited by pepstatin inhibitor. Southern analysis revealed the presence of at least four genes encoding Sap in the C. dublinienisis genome (using as probes SAP1, SAP2, SAP3, and SAP4-6 genes from C. albicans).

Purification and comparison of intracellular proteinase A in Candida spp. isolates from Malaysian and Iranian patients and infected mice

“…In the early hours of nitrogen starvation in the cell, the amount of these enzymes will be increased until optimal nitrogen level is reached [13]. According to Salomé et al [17], there is not much research on intracellular proteinases in fungi which are pathogenic to humans, such as Candida spp. Researchers found that in all fungi, including Candida, the amount of proteinase A enzyme was affected by nitrogen and carbon sources [5,8,18].…”

Evaluation of APR1 Gene Expression in Candida albicans Strains Isolated From Patients With Multiple Sclerosis

“…Intracellular proteinase A is one of the most important enzymes and is produced by the APR1 gene in C. albicans ( 7 ). It is demonstrated that this enzyme has functions in the Candida genus, such as nutrition, help with penetration and invasion, the infection of host tissues and the suppression of the immune system ( 8 , 9 ). In a study conducted by Mechler and Wolf, ( 10 ) the lack of proteinase A led to 30% and 40% reductions in protein degradation under sporulation conditions and sporulation frequency in mutant cells, respectively.…”