Its most likely either a MarinZig Zag Trail or Team Marin, or a Jamis Dakar Sport or Dragon, or a Parkpre Team 825 or 925. All three brands had steel frames with that "ti-plated" finish at the same time period using tubesets from the Tange Prestige family. Parkpre used the Prestige Ultimate Ultralight for example, Jamis just regular Prestige, and Marin used regular Prestige also. Find some old catalogs and look for the cable guide on the head tube and the brake cable noodle on the seat tube.
All prestige meant was that it was a heat-treated double-butted tubeset which was a step above the Tange MTB DB CrMo tubing. Prestige Concept was basically the next step and its where you start to see external profiling of the tube shape, like the flared bottom end of the seat tube to widen its contact area with the BB shell. But it was the Ultimate sub family of Prestige tubesets where the interesting things really started to happen with the butting profiles, and the tube shaping. Ultimate Ultrastrong for example was externally ribbed.