There are 13 words that start with 'protei'.
| protei | proteid |
| protein | proteide |
| proteids | proteins |
| proteides | proteinic |
| proteinase | proteinases |
| proteinuria | proteinurias |
| proteinaceous | |
Note: These 13 words that start with 'protei' are found from the USA & Canada version of the tournament Scrabble word list.