Here are some non-examples of protein, meaning things that are not made of protein or do not have a protein function:

Inorganic Compounds:

* Water (H₂O)

* Salt (NaCl)

* Minerals (iron, calcium, magnesium)

* Diamonds (carbon)

Organic Compounds (not proteins):

* Carbohydrates (sugars, starches, cellulose)

* Lipids (fats, oils, waxes)

* Nucleic acids (DNA, RNA)

* Vitamins (vitamin C, vitamin D)

* Hormones (estrogen, testosterone)

* Pigments (chlorophyll, melanin)

Other:

* Metals (iron, aluminum, gold)

* Plastics (polyethylene, PVC)

* Glass (silicon dioxide)

* Wood (cellulose and lignin)

* Air (nitrogen, oxygen, carbon dioxide)

Important note: Many things that are not proteins might contain proteins as components, but the main structure or function of those things is not protein-based. For example, a cell membrane contains proteins, but it's primarily composed of lipids.