Lactase rhymes with:
diastase, maltase, aerospace, airbase, airspace, ambase, anyplace, birthplace, boldface, bookcase, bouillabaise, briefcase, broadbase, bucase, cityplace, commonplace, cyberspace, database, dbase, diabase, diastase, dnase, electrospace, everyplace, fireplace, footrace, innerspace, interface, lovelace, maltase, marketplace, orthoclase, outpace, parcplace, plagioclase, polymerase, reiterates, scarface, shoelace, showcase, showplace, someplace, staircase, steelcase, steeplechase, streptokinase, suitcase, sybase, typeface, wheelbase, workplace
Lactase sounds like:
lacksadaiscious, lactic, lactose, lakatos, lakotas, lakotas', last's, lasts, lawsuit's, lawsuits, lecates, lectec, legates, leistikow, leucadia's, lickteig, liggett's, light's, lighthouse, lighthouses, lights, lightsey, likud's, liquidates, liquidities, liquids, list's, lists, locates, lockets, lockett's, lockheed's, lockouts, lockwood's, locusts, logistic, logistics, logiudice, logothetis, loguidice, loyalists, lustig, luxottica, luxottica's