The phrase "to come from protein" means that a nutrient or substance is derived from proteins. Protein is an essential macronutrient for humans and other animals, serving as the building blocks for body tissues such as muscles, organs, skin, hair, etc., as well as enzymes, hormones, and antibodies. When we say that something "comes from protein," it means that the nutrient or substance in question is produced through the breakdown of proteins during metabolic processes within our bodies.