複選題28. Please choose the correct answer(s) from the following descriptions: 1. Fructose is not reducing sugar. 2. The α-D-glucose and β-D-glucose interconvert in aqueous solution. 3. GIc(β1→4)Glc could be draw as the following figure. 4. The sugar drawn above is a maltose. 5. Mannose is a C2 epimer of galactose. (A) Only land 2 are correct. (B) 1, 3, and 4 are correct. (C)1 and 5 are correct.(D) 2, 3, and 4 are correct. (E) Only 5 is incorrect.

29. A protein mixture contains proteins A, B, and C (Protein A: homodimer M. = 140,000, pI 8； Protein B: Mr = 113,000, pI 5； Protein C: Mr = 13,000, pI 9). 1. Sandy used SDS-PAGE to separate theses three proteins. The sequence of the protein bands shown in gel from top to bottom is A-B-C. 2. Simon dissolved the protein mixture in 20 mM phosphate buffer (pH 7) and loaded to a cation exchange column equilibrated with the same buffer. Protein B could not bind to the column. 3. Samuel dissolved the protein mixture in 20 mM phosphate bufter (pH 7) and loaded to an anion exchange column equilibrated with the same buffer. Only protein A and C could bind to the column. 4. Silvia used a gel filtration column to separate them, C will be eluted first. 5. Sophie used 2-Dimensional electrophoresis to separate them. The relative positions of these three proteins is like the image below. (A) 1, 2, and 5 are correct. (B) 2 and 4 are incorrect. (C) 1, 3, and 4 are incorrect.(D) Only 2 is correct. (E) Only land 3 are incorrect.

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