Wright C D, Nelson R D
Department of Microbiology, University of Minnesota, Minneapolis 55455.
Biochem Biophys Res Commun. 1988 Jul 29;154(2):809-17. doi: 10.1016/0006-291x(88)90212-4.
We have previously demonstrated the ability of human neutrophil myeloperoxidase to bind to cell wall mannan polysaccharide isolated from Candida albicans. This binding capacity provides for association of the enzyme with target yeast which is essential for efficient candidacidal activity. In this report, we further consider the role of the mannan-binding property of myeloperoxidase in the candidacidal activity of the enzyme. Solubilized mannan antagonizes binding of the enzyme to yeast, suggesting that mannan may be a primary component of the fungal cell wall which serves as a target for binding of myeloperoxidase. Myeloperoxidase is shown to form complexes with both solubilized mannan and Candida yeast, with Kds of 0.97 x 10(-5) M and 1.2 x 10(-5) M, respectively. The interaction between myeloperoxidase and mannan does not allow the enzyme to readily dissociate from the surface of target yeast. As a result, the enzyme may be unable to dissociate from dead yeast to become available for binding to additional fungal targets.
我们之前已经证明了人类嗜中性粒细胞髓过氧化物酶能够与从白色念珠菌中分离出的细胞壁甘露聚糖多糖结合。这种结合能力使得该酶能够与靶酵母结合，这对于高效的杀念珠菌活性至关重要。在本报告中，我们进一步探讨了髓过氧化物酶的甘露聚糖结合特性在该酶杀念珠菌活性中的作用。可溶性甘露聚糖可拮抗该酶与酵母的结合，这表明甘露聚糖可能是真菌细胞壁的主要成分，作为髓过氧化物酶的结合靶点。结果表明，髓过氧化物酶与可溶性甘露聚糖和念珠菌酵母均能形成复合物，解离常数分别为0.97×10⁻⁵M和1.2×10⁻⁵M。髓过氧化物酶与甘露聚糖之间的相互作用使得该酶不易从靶酵母表面解离。因此，该酶可能无法从死亡酵母中解离出来，从而无法再与其他真菌靶点结合。
