Protein molecules have the property of denaturation. What it is? Why do proteins lose their function

Protein molecules have the property of denaturation. What it is? Why do proteins lose their function as a result of denaturation?

The denaturation property is the property of a protein molecule to change its configuration under the influence of various factors, usually unfavorable for a living organism. The primary structure of a protein, namely the sequence of amino acids in its molecule, remains unchanged, while the secondary, tertiary and quaternary structure of the protein is destroyed, because hydrogen and ionic bonds are destroyed during denaturation. Protein, figuratively speaking, “unfolds” to a linear molecule. The loss of its usual structure by a protein inevitably leads to the loss of its functions.