James became the fifth player in NBA history to reach the milestone after scoring 20 points with 10 rebounds and 11 assists in the defeat.
"Turnovers killed us," said James.
"We were doing a hell of a job over the last seven games averaging only 12.5 turnovers. Tonight we had 22 for 27 points."
The Grizzlies were without key players Ja Morant and Dillon Brooks but still won, with Jaren Jackson Jr scoring 25 points and Desmond Bane adding 23.
Memphis have won six of their past seven games and have a record of 15 wins and 11 defeats this season, while the LA Lakers have a 13-13 record.
"Our biggest battle, our biggest problem this year is consistency," said Lakers coach Frank Vogel.
"Once we take one step forward we fall back, we have a disappointing performance. We have to find a way to catch ourselves from that."
Elsewhere, Donovan Mitchell scored 22 points and Rudy Gobert had 17 points and 21 rebounds for the Utah Jazz as they beat the Philadelphia 76ers 118-96.
The San Antonio Spurs also earned a win as Derrick White scored 23 points in their 123-111 victory over the Denver Nuggets.