The last two tubs of High 5 energy drink I have bought have had added protein. I guess they wouldn’t sell it if nobody would buy it. Their claim:
Energy Drink with Protein comes in a scientifically formulated 4:1 ratio of carbohydrate to protein. The advanced carbohydrate and electrolyte mix is designed to help you sustain your performance during endurance exercise and aid your recovery of normal muscle function afterwards.
And a so called independent review: