- 背景資料
棉子糖(raffinose)、水蘇糖(stachyose)、毛蕊花糖(verbascose)為”棉子糖系列寡醣”（oligosaccharides in raffinose series）的其中一種。其結構主要由蔗糖以α(1→6)醣苷鍵鍵結半乳糖所構成。
棉子糖(raffinose)➡️三糖➡️半乳糖α(1→6)葡萄糖α(1→2)果糖
水蘇糖(stachyose)➡️四糖➡️半乳糖α(1→6)半乳糖α(1→6)葡萄糖α(1→2)果糖
毛蕊花糖(verbascose)➡️五糖➡️半乳糖α(1→6)半乳糖α(1→6)半乳糖α(1→6)葡萄糖α(1→2)果糖
人體的腸道因無法分泌α-半乳糖苷酶(α-galactosidase)，故無法完全分解具有α-半乳糖苷寡醣之物質(例如:棉子糖、水蘇糖、毛蕊花糖...等物質)，此類物質進入人體之後，最終則會被人體的腸內菌所利用，進而產生發酵作用，部分腸內菌發酵時可能會有氣體產生，故會導致脹氣、腹痛等身體不適症狀。此外，因部分的寡醣具有促進益生菌生長、抑制壞菌數量...等功能，故被稱為益生元 (prebiotics)。
- 操作流程(PROCEDURE)
- 樣品準備(SAMPLE PREPARATION)
1. Sample dilution.
The amount of D-galactose present in the cuvette (i.e. in the 0.2 mL of sample being analysed) should range between 4 and 83 μg (i.e. raffinose in the sample taken should range between approx. 12 and 250 μg). The sample solution must therefore be diluted sufficiently to yield a raffinose concentration of between 0.2 and 1.25 g/L.
2. Sample clarification.
a. Solutions:
Carrez I solution. Dissolve 3.60 g of potassium hexacyanoferrate (II){K4[Fe(CN)6].3H2O} (Sigma cat. no. P9387) in 100 mL of distilled water. Store at room temperature.
Carrez II solution. Dissolve 7.20 g of zinc sulphate (ZnSO4.7H2O) (Sigma cat. no. Z4750) in 100 mL of distilled water. Store at room temperature.
Sodium hydroxide (NaOH, 100 mM). Dissolve 4 g of NaOH in 1 L of distilled water. Store at room temperature.
b. Procedure:
Pipette the liquid sample into a 100 mL volumetric flask which contains approx. 60 mL of distilled water, or weigh sufficient quantity of the sample into a 100 mL volumetric flask and add 60 mL of distilled water. Carefully add 5 mL of Carrez I solution, 5 mL of Carrez II solution and 10 mL of NaOH solution (100 mM). Mix after each addition. Fill the volumetric flask to the mark, mix and filter.
3. General considerations.
(a) Liquid samples: clear, slightly coloured and approximately neutral, liquid samples can be used directly in the assay.
(b) Acidic samples: if an acidic sample is to be used undiluted (such as red wine or coloured fruit juice), the pH of the solution should be increased to approx. 8.6 using 2 M NaOH, and the solution incubated at room temperature for 30 min.
(c) Carbon dioxide: samples containing carbon dioxide should be degassed by increasing the pH to approx. 8.6 with 2 M NaOH and gentle stirring, or by stirring with a glass rod.
(d) Coloured samples: an additional sample blank, i.e. sample with no β-GalDH, should be performed in the case of coloured samples.
(e) Strongly coloured samples: if used undiluted, strongly coloured samples should be treated by the addition of 1 g/100 mL of polyvinylpolypyrrolidone (PVPP). Stir for 2 min and then filter.
(f) Solid samples: homogenise or crush solid samples in distilled water and filter if necessary.
(g) Samples containing fat: extract such samples with hot water at a temperature above the melting point of the fat, e.g. in a 100 mL volumetric flask. Adjust to 20°C and fill the volumetric flask to the mark with water. Store on ice or in a refrigerator for 15-30 min and then filter. Discard the first few mL of filtrate and use the clear supernatant (which may be slightly opalescent) for the assay. Alternatively, clarify with Carrez reagents.
(h) Samples containing protein: deproteinise samples containing protein with Carrez reagents.
商品特色
商品規格
- 商品規格 120 檢測反應
Bottle 1:
Buffer (25 mL, pH 8.6) containing sodium azide (0.02% w/v) as a preservative.
Stable for > 2 years at 4°C.
Bottle 2:
NAD+.
Stable for > 5 years below -10°C.
Bottle 3:
D-Galactose dehydrogenase plus galactose mutarotase suspension (2.5 mL).
Stable for > 2 years at 4°C.
Bottle 4:
α-Galactosidase (pH 4.6), lyophilised powder.
Stable for > 4 years below -10°C.
Bottle 5:
Galactose standard solution (5 mL, 0.4 mg/mL) in 0.02% (w/v) sodium azide.
Stable for > 2 years; store sealed at 4°C.
Bottle 6:
Raffinose control powder (~ 4% w/w raffinose in mannitol; the exact concentration is stated on the vial label).
Stable for > 5 years; store sealed at room temperature.
