%0 Journal Article %A Shafer, William M. %A Morse, Stephen A. %T Cleavage of the Protein III and Major Iron-Regulated Protein of Neisseria gonorrhoeae by Lysosomal Cathepsin G %D 1987 %J Microbiology, %V 133 %N 1 %P 155-162 %@ 1465-2080 %R https://doi.org/10.1099/00221287-133-1-155 %I Microbiology Society, %X Incubation of either 125I-labelled or unlabelled Neisseria gonorrhoeae with enzymically active preparations of human polymorphonuclear leucocyte lysosomal cathepsin G revealed that surface-exposed outer-membrane proteins were susceptible to proteolytic modification. Electroimmunoblotting experiments confirmed that outer-membrane protein III (PIII) and the major iron-regulated protein (MIRP), two conserved gonococcal proteins, were cleaved by cathepsin G. A direct relationship was observed between susceptibility to the antibacterial properties of cathepsin G and cleavage of PIII among isogenic strains differing in their level of resistance to the bactericidal activity of cathepsin G. Although the antibacterial property of cathepsin G is known to be independent of serine-esterase activity, the data suggest that gonococcal outer-membrane proteins are involved in the binding of cathepsin G, and that variation in the level of resistance reflects the degree to which target outer-membrane proteins such as PIII are exposed. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-133-1-155