LOS ANGELES >> The contradictions in Manny Pacquiao’s dual careers are unmistakable.

He is embracing a humanitarian campaign in his significant day job, and is being asked to knock a man out in his lucrative work at night.

Yet as much as Pacquiao at this week’s news conference discussed his fight Saturday night, even more time was spent on how he would be wearing yellow boxing gloves as he takes on Shane Mosley, imploring anyone listening to don yellow clothing to show unity in the worldwide fight to end poverty.

Then, someone asked Pacquiao the unexpected.

Does the world’s greatest fighter still have the killer instinct?

Pacquiao paused, as if repeating the question to himself, truly assessing it and forcing the answer everyone wanted to hear.

“Yes,” he answered. “I’ll always have a killer instinct.”

On the heels of two unanimous-decision victories last year against Joshua Clottey and Antonio Margarito — in the latter of which he asked a beaten Margarito in the 11th round, “You OK?” — Pacquiao’s compassionate nature has crept uncomfortably into his efforts previously celebrated for their merciless fury.

“Manny becomes friends with these guys over the course of 12 rounds, and he does the same thing with his sparring partners — he’ll stop hitting them,” Pacquiao trainer Freddie Roach said. “I say, ’Don’t be friends, one punch can change everything.”’

Saturday, Pacquiao (52-3-2, 38 knockouts) seeks to extend his impressive 13-fight winning streak against the 39-year-old Mosley.

“People want to see the Manny of old, the guy who dominates his opponents, leaving them to be rescued by the referee,” said Nick Giongco, the Manila Bulletin boxing reporter.

Roach, after what he describes as his fighter’s best training camp ever, is urging Pacquiao to go for the kill, to become the first man to knock out Mosley (46-6-1, 39 KOs).

“You knock out Shane, you make more money the next fight,” Roach said he has told Pacquiao. “That, he understands.”

Roach wants Pacquiao to separate himself from unbeaten Floyd Mayweather Jr. in the mythical pound-for-pound argument. Mayweather dissected Mosley after being hit hard in the second round of their May 2010 bout. But Mayweather couldn’t knock out the former three-division world champion from Pomona.

Pacquiao has been unmistakably affected by his work as a congressman in the Philippines, where he has undertaken projects such as typhoon relief, constructing a hospital and improving literacy efforts to assist his countrymen suffering through Third World conditions.

You don’t intensify a lust for blood doing those things.

Pacquiao’s platform as the most gifted boxer in the world gives him unprecedented power to promote the causes closest to his heart. His time meeting with the masses on the campaign trail in the Philippines has made him more comfortable than ever in asserting his voice.

He was given a personal audience with President Barack Obama earlier this year and ultimately could be elected president of the Philippines.

“It’s important to me to give happiness, enjoyment to people, to keep improving myself always,” Pacquiao said. “It’s very important to me to announce unity to help poverty and help the people in my country. We can help people if we work together.”

In the meantime, he is charged with repeating what got him here, the gritty — yes, violent — business of outclassing his opponent with rapid punching, speed and footwork.

Roach revealed that Pacquiao told him late in the lopsided victory over Margarito there no longer was a “need to hurt him.” A similar scenario played out before Oscar De La Hoya quit on the stool against him.

Even as Pacquiao promoted this fight, someone on Showtime’s “Fight Camp 360” crew asked him to duplicate his menacing glare from a photo years ago, when he wasn’t far removed from being that poor Filipino youth fighting for survival.

Roach recalls the Pacquiao from back then, the kid who nearly lost by exhausting his energy after betting his entire purse he’d knock out Nedal Hussein before the end of the fifth round.

For Showtime, Pacquiao couldn’t re-enact that mean look without cracking a smile.

And he certainly won’t be gambling with his Mosley purse, which is expected to reach $25 million.

“The problem is that as the opponent stays around, Manny’s mercy comes around,” Pacquiao’s veteran promoter, Bob Arum, said. “Ali had that, too, where he’d ask the referee to stop the fight.

“Beating up the guy is part of the sport. Once the opponent is helpless, it’s no longer a sport. It’s brutality. If the crowd still wants that finish even when the other guy’s clearly done, I must say they’re sick.”

Said Pacquiao: “I’m not aiming for a knockout. I focus on doing my best. If the knockout comes, fine. If not, that’s OK.”