In October 2004, when Tuyakbai was Speaker in parliament and the number-two man in President Nazarbayev's Otan party, he quit both posts to protest against elections a month earlier, which he labelled "a farce".
"I'd long been protesting inside, but thought that mistakes were inevitable in a transition period and they'd be put right later on," Tuyakbai said.
"The September 2004 polls came as the last drop."
His defection was seized on with hope by members of the fledgling pro-democracy opposition and he became leader of the alliance, For a Fair Kazakhstan. He is running for president under its banner.
As a presidential candidate, people threw stones at him and young people shouted abuse during his meetings with voters.
He has campaigned with virtually no access to TV channels, which are largely controlled by Nazarbayev's family and supporters.
Nazarbayev, meanwhile, has dominated media coverage of the presidential campaign, with accounts focusing on the stability and steady economic growth under his virtually undisturbed 16-year rule.
Along with those impediments, Tuyakbai also suffers from a charisma deficit and a late start in challenging Nazarbayev.
Having spent little over a year outside the higher echelons of the ruling party, he has not had much time to try to convince voters that he is a truly democratic alternative to Nazarbayev, or to unite an opposition weakened by factional disputes.
Tuyakbai, 57, started his working life on a collective farm. A law school graduate, he became chief prosecutor in 1990, holding the post until 1995. He then served as the head of state investigations and as the chief military prosecutor.
In 1999 he won a seat in parliament and was elected its Speaker.
Tuyakbai accuses Nazarbayev of allowing institutionalised corruption and enriching himself and his family at the expense of national wealth, and of empty promises of democratic changes.
"What we are seeing today isn't an election process but an attempt by Nazarbayev to consolidate his family's political and economic power," Tuyakbai said.
"I'd long been protesting inside, but thought that mistakes were inevitable in a transition period and they'd be put right later on"
leader of the pposition alliance For a Fair Kazakhstan
Tuyakbai has proposed a new constitution that would limit presidential powers, open the way for political competition and ensure the independence of judges.
He is also offering a package of economic reforms aimed at eliminating poverty and making sure that ordinary people benefit from the wealth of natural energy resources.
Tuyakbai is calling also for transparency in energy contracts with Western investors and a review of big privatisation deals concluded under Nazarbayev.
The opposition candidate's campaign was plagued by the theft and burning of his campaign literature, harassment of his activists and regular seizures of newspapers that back him.
He was unable to rent billboard space, and many of his posters have been ripped down.
But Tuyakbai says victory is still possible: "All we need is an honest vote count."