The 24-year-old has been heavily linked with a move to Stamford Bridge of late, but has elected to stay in Ukraine and join the league leaders, who are 13 points clear at the top
The Brazilian attacker's form for his club caught the eye of a host of clubs across Europe, including Champions League holders Chelsea.
However, the Donbass Arena outfit have now pounced for the 24-year-old, activating his release clause.
"On January 10, the presidents of Shakhtar and Metalist negotiated the transfer of Taison from the Kharkiv club to the Donetsk team," a statement on the club's official site read.
"Shakhtar paid $20m (€15m), and we got a player who really wanted to join our team. The Brazilian player's five-year contract started on January 11."
The attacker moved to Metalist from Internacional in 2010, and made 57 league appearances for the club, scoring 13 goals.
Shakhtar have enjoyed a fantastic Ukrainian Premier League season thus far, and currently sit 13 points clear of Dnipro in the table, having won 17 of their 18 games.
They face Borussia Dortmund in the last 16 of the Champions League.