_______________ determines the exact mass of every peptide fragment in a purified protein, which then allows the protein to be identified from a database that contains a list of every protein thought to be encoded by the genome of the organism in question.

Butyrate can function as ： A: protein methylation B: Protein acetylation C: Protein phosphorylation D: Protein deacetylation

the complementary effect of food protein refers to A: Provide enough calories，can save food protein intake B: Provide a variety of vitamins, can save food protein intake C: Adequate supply of essential fatty acids can improve the nutritional value of protein D: Eating a mix of different types of protein has a higher nutritional value than eating one alone

When an enzyme protein is purified and assayed step by step, _____________________________________ with each step. A: oth activity and total protein generally increase B: activity increases but total protein generally decreases C: oth activity and total protein generally decrease D: activity decreases but total protein generally increases

Among the following phenomena, ( ) is not the main manifestation of the effect of denaturation on protein. A: The solubility of protein increases B: The protein's water holding capacity drops C: Protein is easily digested and absorbed D: The biologically active protein loses its biological activity