Question

The percentage of Se in peroxides enzyme is 0.5% by mass (atomic mass of Se = 78.4 amu). Then, the minimum molecular mass of enzyme which contains not more than one Se atom is

• A. $1.568\times 10^{4}amu$
• B. $1.568\times 10^{7}$ amu
• C. $1.568\times 10^{3}$ amu
• D. $1.568\times 10^{6}$ amu

Answer 1

Answer: (A)

In peroxidase anhydrous enzyme, $0.5 gm$
Se is present in $100 gm$ of the enzyme.
In a molecule of enzyme, one Se atom must be present.
Hence 78.4gm Se will be present in $\frac{100}{0.5} \times 78.4=1.568 \times 10^{4}$