Alex Yemenidjian puts his money where his mouth is.Peripatetic preacher of a turnaround gospel at MGM since being named chairman and CEO of the studio in April 1999, Yemenidjian has newly acquired some $2.3 million in Metro-Goldwyn-Mayer stock at an average price of $24.38 per share. Disclosed in a regulatory filing Tuesday, Yemenidjian’s purchase of 93,260 shares was conducted on the open market Monday. The transactions bring his MGM holdings to about 100,000 shares in total, officials said. That compares to some 179 million MGM shares held by billionaire financier Kirk Kerkorian, who has an 87% stake in the studio. Yemenidjian also holds unexercised options on another 10 million shares in MGM. MGM shares closed down 13¢ at $24.94 on Tuesday.