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The complete amino acid sequence of human complex-forming glycoprotein heterogeneous in charge (protein HC) from one
Insights
The complete amino acid sequence of human complex-forming glycoprotein heterogeneous in charge (protein HC) was determined. No sequence variability was found, indicating other factors cause its charge heterogeneity.
Area of Science:
- Biochemistry
- Proteomics
- Human Genetics
Background:
- Human complex-forming glycoprotein heterogeneous in charge (protein HC) exhibits charge heterogeneity within individuals.
- Understanding the primary structure of protein HC is crucial for elucidating its functional variations.
Purpose of the Study:
- To determine the complete amino acid sequence of human protein HC.
- To investigate whether amino acid sequence variability accounts for protein HC's charge heterogeneity.
Main Methods:
- Automatic Edman degradation of the intact polypeptide chain.
- Chemical and enzymatic fragmentation of protein HC.
- Analysis of primary structure using automated sequencing techniques.
Main Results:
- The polypeptide chain of protein HC consists of 182 amino acid residues.
- A calculated molecular weight of 20,621 was determined for protein HC.
- No amino acid sequence variability was detected in the analyzed protein HC, despite observed charge heterogeneity.
Conclusions:
- The amino acid sequence of human protein HC is invariant and does not explain its charge heterogeneity.
- Protein HC shares high sequence similarity with human alpha 1-microglobulin, with 15 additional residues.
Abstract:
The complete amino acid sequence of the single polypeptide chain of human complex-forming glycoprotein heterogeneous in charge (protein HC) isolated from a single individual is reported with the supporting data. The primary structure was determined by automatic degradation of the intact chain and of fragments obtained by chemical and enzymatic degradations of the native or reduced and S-carboxymethylated protein. The polypeptide chain of protein HC contained 182 amino acid residues with a calculated molecular weight of 20,621. No amino acid sequence variability was found and such variability can therefore not explain the great charge heterogeneity of protein HC in a single individual. The amino acid sequence of protein HC was nearly identical to the one reported for human alpha 1-microglobulin in a research communication but contained 15 additional residues.