The 23-year-old only joined the Portuguese outfit during the summer from Olhanense.
However, after Braga had accepted a bid believed to be in the region of £3m from Shakhtar, the Brazilian has agreed a five-year contract at the Donbass Arena.
"Normally I am a defender, but I like to go forward too," Ismaily told the club's official website. "I love to take part in my team's attacks. I have already adapted well to European football so believe I will be able to hit my stride at Shakhtar pretty quickly.
"I heard a lot about Shakhtar in Brazil. They are regarded as an up and coming club. I also knew they had a lot of Brazilian players, but when I arrived here I was astonished and amazed by what I saw. This is a fantastic club."
Ismaily will not be eligible to play in the Champions League for his new employers because of his previous involvement in the competition with Braga earlier this season.