title: An equation to estimate the difference between theoretically predicted and SDS PAGE-displayed molecular weights for an acidic peptide.
abstract: The molecular weight (MW) of a protein can be predicted based on its amino acids (AA) composition. However, in many cases a non-chemically modified protein shows an SDS PAGE-displayed MW larger than its predicted size. Some reports linked this fact to high content of acidic AA in the protein. However, the exact relationship between the acidic AA composition and the SDS PAGE-displayed MW is not established. Zebrafish nucleolar protein Def is composed of 753 AA and shows an SDS PAGE-displayed MW approximately 13 kDa larger than its predicted MW. The first 188 AA in Def is defined by a glutamate-rich region containing ~35.6% of acidic AA. In this report, we analyzed the relationship between the SDS PAGE-displayed MW of thirteen peptides derived from Def and the AA composition in each peptide. We found that the difference between the predicted and SDS PAGE-displayed MW showed a linear correlation with the percentage of acidic AA that fits the equation y = 276.5x - 31.33 (x represents the percentage of acidic AA, 11.4% ≤ x ≤ 51.1%; y represents the average ΔMW per AA). We demonstrated that this equation could be applied to predict the SDS PAGE-displayed MW for thirteen different natural acidic proteins.
authors: MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou, 310058 China.
authors: Yihong
authors: Y
authors: Guan
authors: MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou, 310058 China.
authors: Qinfang
authors: Q
authors: Zhu
authors: MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou, 310058 China.
authors: Delai
authors: D
authors: Huang
authors: MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou, 310058 China.
authors: Shuyi
authors: S
authors: Zhao
authors: MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou, 310058 China.
authors: Li
authors: L
authors: Jan Lo
authors: MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou, 310058 China.
authors: Jinrong
authors: J
authors: Peng
mesh_terms: D000143:Acids / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D008956:Models, Chemical; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry*; D058207:Sumoylation; D054875:Ubiquitination; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000737:chemistry
chemical_list: D000143:Acids; D010455:Peptides; D029961:Zebrafish Proteins