The interaction of apomyoglobin and its mutant forms with phospholipid membranes was studied using tryptophan fluorescence and circular dichroism in the far UV region. It is shown that a negatively charged phospholipid membrane can have a dual effect on the structure of protein molecule upon their interaction. On the one hand, the membrane induces denaturation of the protein native structure to its intermediate state, acting as a moderate denaturing agent. On the other hand, it can stabilize the structure of unfolded protein to the same intermediate state, acting as a moderate structuring agent. The kinetics of interaction between apomyoglobin and its mutant forms and the phospholipid membrane depends on the membrane surface charge. Here the interaction rate depends on the concentration of phospholipids vesicles and stability of protein molecule, which increase with a decrease in the latter. The roles of these factors in the folding of membrane proteins and the choice of the targeted delivery pathways for protein drugs are discussed.