Answer:
Proteins are digested in the body when ingested food from a protein source, is broken down in the stomach by enzymes like Chymotrypsin, trypsin which are both proteins, their common goal is to convert protein into a more simple form or simplest form ( Amino acids). This enzyme (Chymotrypsin and trypsin) are Proteins and they act as biological catalysts that are responsible for breaking proteins down.
An example of how Proteins are transported by fellow proteins is the case of Ferritin. Ferritin is an essential protein in the cell of the body that regulates the amount of iron available to the body. This is important for the hemoglobin in red blood cells.