Six people were killed and 81 others wounded in Sunday's explosion.
Turkey's Interior Minister Suleyman Soylu said police had detained 22 suspects, including the person who had planted the bomb.
"The person who carried out the incident, left the bomb, was detained. Previously, around 21 other people had been detained," Soylu said.
Television news reports showed images of a person, who appeared to be a woman, leaving a package below a raised flower bed in Istiklal Avenue, a popular spot for shoppers and tourist, with a tramline running the length of the street.
Soylu said the order for the attack on Istanbul's Istiklal Avenue was given in Kobani, a city in northern Syria, where Turkish forces have carried out operations against the Syrian Kurdish YPG militia in recent years.
"We have evaluated that the instruction for the attack came from Kobani," Soylu said, adding that bomber had passed through Afrin, another region in northern Syria.
Fifty people were discharged from hospital after Sunday's attack, which sparked concerns that Turkey could be targeted with more bombings and attacks, like the series of attacks that it suffered between mid-2015 and 2017.
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