$-$Galactosidase $(-$gal$)$ is a hydrolase enzyme that catalyzes the hydrolysis of $-$galactosides into monosaccharides. A $0\mathrm{.}571g$ sample of $-$galactosidase is dissolved in water to make $0\mathrm{.}140L$ of solution, and the osmotic pressure of the solution at $25C$ is found to be $0\mathrm{.}869\frac{m}{b}ar.$ Calculate the molecular mass of $-$galactosidase.

molecular mass: