"AminoSweet is a low calorie sweetener that tastes exactly like sugar. It is made from two building blocks of protein just like those found naturally in many everyday foods such as meat, fish, cheese, eggs and milk. AminoSweet is digested by the body in exactly the same way as these other protein foods and so does not bring anything new to the diet."
The quote is from the Aminosweet Information Service, created by the company Ajinomoto, one of the makers of aspartame. Aspartame made by The NutraSweet Company is known as Nutrasweet.