Given a reference text about Mikel Artetxe Guezuraga, tell me when he turned professional and what his biggest wins are.
Mikel Artetxe Guezuraga turned professional in 1999 and had the biggest wins of his career in 2006 with a stage win in the Vuelta a Asturias and the sprints classification in the Troféu Joaquim Agostinho.