I think it might be the first one: hiv infections. (hope this helps!)
Enzymes are made of strings of amino acids chemically bonded to one another. These bonds give each enzyme a unique structure, which determines its function. They mostly break down carbohydrates and fats. Once a protein source reaches your stomach, hydrochloric acid and enzymes called proteases break it down into smaller chains of amino acids. Amino acids are joined together by peptides, which are broken by proteases.
