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[求助]
幫忙翻譯一段實(shí)驗(yàn)操作步驟,條理清楚點(diǎn)就最好不過啦,萬(wàn)分感激
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這是我實(shí)驗(yàn)的一部分,自己翻譯的總感覺不對(duì),拜托各位大俠幫忙翻譯一下,只要寫出每個(gè)步驟怎么做就可以了,謝謝謝謝 2.2. Determination of total-SH, free-SH and S–S groups The amount of different sulphydryl group species was determined in products with a modified Ellman’s reaction (Bu¨ rki, 1977). Ellman’s reagent was prepared by dissolving 10 mg 5,50-dithio-bis(2-nitrobenzoic acid), DTNB, in 10mL 0.05M Tris/0.01 M EDTA-buffer. The pH was adjusted with 4M HCl to reach a pH of 7.0. The solution was degassed by ultrasound. Free sulfhydryl groups were determined by mixing 0.5mL milk with 2.5mL of 0.1M borate/0.02M EDTA, pH 8.3 buffer and 50 mL DTNBreagent in a 1 cm cell. After 20 min, the extinction at 412nm was measured. After addition of one drop of 30% H2O2, the extinction at 412nm was measured again; this gives the blank value. Concentration of free-sulphydryl groups in the sample was calculated using a calibration curve with cysteine. Total sulphydryl groups was determined by mixing 0.5mL milk with 2.5mL 0.05M borate/0.010M EDTA, pH 8.3/8.33M urea buffer and 50 mL DTNB-reagent in a 1 cm cell. Extinction at 412 nm was measured after 15 min, and the blank as above, after adding one drop of 30% H2O2. The concentration of total sulphydryl groups was calculated from a calibration curve with bovine serum albumin, which contains one buried sulphydryl group in its three-dimensional structure that is denatured by addition of urea in the buffer. The concentration of masked sulphydryl groups (MSH) was calculated by subtracting the concentration of free sulphydryl groups (FSH) from the concentration of total sulphydryl groups (TSH). The concentration of total protein-bound cysteine was determined by incubating 0.25mL milk with 1.25mL 0.1M Tris–HCl/12mM EDTA/0.6% SDS, pH 7.6/8 M ureum/ 10mM DTT buffer at 35 1C for 1 h. Subsequently, reduced protein and DTT were separated by eluting 0.25mL mixture on a GPC-column, using 75mM Tris/10mM EDTA/0.45% SDS, pH 7.5/6M urea buffer. After washing with 1.25mL buffer, 3mL elution fluid was collected. The collected fluid was mixed with 0.1mL 0.5M Tris-buffer and 50 mL DTNB-reagent. The extinction at 412 nm was measured between 15 and 90 min after addition of DTNB-reagent. The blank was again measured after addition of one drop of 30% H2O2. The concentration of S–S bridge was calculated by subtracting the concentration of total sulphydryl groups from the sulphydryl concentration after reduction, followed by a division by 2. |
鐵桿木蟲 (著名寫手)
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先上傳翻譯的第一段,隨后上傳后兩段。 2.2. 總SH,游離(自由)SH和S-S基團(tuán)的測(cè)定 采用改進(jìn)的Ellman反應(yīng)(Bu¨ rki, 1977) 確定了產(chǎn)物中不同巰基(基團(tuán))物種的數(shù)量。Ellman試劑按如下法制備:10 mg 5,5-二硫代-雙(2-硝基苯甲酸),DTNB,溶解于10 mL 0.05 M Tris(注釋)/ 0.01M EDTA 緩沖溶液中。用4 M鹽酸調(diào)整pH值至7.0。溶液超聲脫氣。自由巰基基團(tuán)按如下法確定:將0.5mL牛奶與2.5mL 0.1M硼酸鹽/0.02M EDTA、pH 8.3緩沖溶液和50mL DTNB試劑混合,(取適量,否則邏輯上不通順)于1cm 池長(zhǎng)的比色皿中。20分鐘后,測(cè)量412納米處的消光系數(shù)。 Tris可能是三異丙基乙磺;蛉u甲基氨基甲烷,這要根據(jù)實(shí)驗(yàn)部分中的“儀器及試劑”或其結(jié)構(gòu)式來(lái)確認(rèn)。 |
鐵桿木蟲 (著名寫手)
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現(xiàn)上傳譯文的后兩段: 滴加一滴30% 過氧化氫后, 再次測(cè)量412 nm處的消光系數(shù),并得出空白值。樣品中自由巰基基團(tuán)的濃度采用與半胱氨酸校準(zhǔn)曲線來(lái)計(jì)算?値基基團(tuán)按如下法確定:將0.5 mL牛奶與2.5 mL 0.05 M硼酸鹽/0.01M EDTA,pH8.3/8.33 M尿素緩沖溶液和50 mL DTNB-試劑混合,取適量于1cm 池長(zhǎng)的比色皿中。15分鐘后,測(cè)量412納米處的消光系數(shù),并同上滴加一滴30% 過氧化氫后測(cè)量空白值。總巰基基團(tuán)的濃度可采用與牛血清白蛋白的校準(zhǔn)曲線來(lái)計(jì)算,在其三維結(jié)構(gòu)中包含一個(gè)隱藏的巰基基團(tuán),在緩沖溶液中加入尿素可(使其)變性。 掩蔽(隱藏)的巰基基團(tuán)(MSH)的濃度可如下計(jì)算:總巰基基團(tuán)(TSH)的濃度減去自由巰基基團(tuán)(FSH)的濃度。與蛋白質(zhì)相結(jié)合的半胱氨酸的總濃度可如下法確定:在35 攝氏度1小時(shí)內(nèi),配制(培養(yǎng))0.25 mL牛奶1.25mL 0.1M Tris-HCl/12 mM EDTA/0.6% SDS,pH7.6/8 M 尿素/10 Mm DTT緩沖溶液;隨后,被還原的蛋白質(zhì)和DTT在一個(gè)GPC(凝膠滲透)-色譜柱上以0.25 mL 混合液洗脫分離,使用75 mM Tris/10 mM EDTA/0.45% SDS,pH7.5/6 M尿素緩沖溶液。用1.25 mL緩沖溶液洗滌后,收集3mL洗脫液。收集的液體與0.1 mL 0.5 M Tris 緩沖溶液和50 mL DTNB 試劑混合。在加入DTNB 試劑15至90分鐘后,測(cè)量412納米處的消光系數(shù)。滴加一滴30% 過氧化氫后再次測(cè)量空白值。S-S橋的濃度可如下計(jì)算:從還原后巰基的濃度減去總巰基基團(tuán)的濃度,然后除以2。 |
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