When vitamin D drugs are used in an attempt to arrest certain types of cancer, for example, the tumor responds by making more of this enzyme, according to study leader Dr. Glenville Jones of Queen's University in Kingston, Ontario.

"If we can block the tumor response, we should be able to successfully treat some tumors with vitamin D compounds," Jones said in a statement.

"The effectiveness of vitamin D therapy is partly dependent on how quickly it will be broken down, and by studying the enzyme responsible for breaking down the vitamin we hope to develop a way to prevent this from happening by blocking that response."

Vitamin D deficiency has also been correlated with other diseases, including multiple sclerosis, muscle weakness and bone-related disorders, said Jones.

The discovery, first observed in Jones's lab by undergraduate biochemistry student Brendan O'Leary, reveals that changing a single amino acid in the hydroxylase enzyme will cause it to take a completely different pathway.