Purifying sulphydryl oxidase enzyme derived from whole milk - esp. prior to immobilising on glass beads; used to remove boiled taste of heated milk

摘要

Process comprises (a) preparing a crude, non-purified sulphhydryl oxidase enzyme (I)-fraction from raw whole milk; (b) dissolving this non-purified (I)-fraction in a dil. neutral buffer soln.; (c) equalising the non-purified (I)-fraction; (d) exposing the non-purified (I)-fraction in buffer soln. to a separate treatment, to separate a first (I)-fraction of molecularly larger materials; (e) concentrating the first enzyme fraction, esp. by ultra-filtration, to obtain a 2nd enzyme fraction and (f) sepg. this 2nd enzyme fraction, pref. by centrifuging, to remove molecularly smaller materials and isolate (I). The isolated enzyme is esp. dissolved in a neutral buffer soln., to obtain a 3rd enzyme fraction; the enzyme is sepg. from molecularly smaller materials; isolated to obtain an enzyme having higher specified activity, and pref. immobilised on glass beads. The purified, immobilised (I) is used (i) to remove the boiled taste from milk heat-treated above 68 degrees C, and (ii) in biosynthesis of disulphides in cartain proteins. Sterilised treated milk can be obtd. which is marketable and resists storage at ambient temps. The specific activity of purified, immobilised (I) is >=50 (>=100) x higher than that of the crude (I)-fraction obtd. from the whey fraction sepd. from raw whole milk-derived skim milk.