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Human urinary prokallikrein--structural analysis on activation mechanism
S Takahashi1, A Irie, Y Katayama
1Department of Biochemistry, National Cardiovascular Center Research Institute, Osaka, Japan.
Advances in Experimental Medicine and Biology
|January 1, 1989
Summary
The complete amino acid sequence of human urinary kallikrein was determined, revealing a 238-residue polypeptide. This finding clarifies the enzyme
Area of Science:
- Biochemistry
- Enzymology
- Proteomics
Background:
- Human urinary kallikrein is a key enzyme in the kallikrein-kinin system.
- Understanding its structure is crucial for elucidating its function and regulation.
Purpose of the Study:
- To determine the complete amino acid sequence of human urinary kallikrein.
- To identify potential post-translational modification sites and activation pathways.
Main Methods:
- Amino acid sequencing of purified human urinary kallikrein.
- Analysis of prokallikrein structure and activation intermediates.
Main Results:
- The complete amino acid sequence of human urinary kallikrein, a 238-residue single polypeptide, was elucidated.
- A seven-amino acid propeptide was identified in prokallikrein.
- Three potential glycosylation sites (Asn-X-Thr/Ser) were located at positions 78-80, 84-86, and 141-143.
- Trypsin-mediated hydrolysis of Arg(-1)-Ile(1) and Arg(87)-Gln(88) bonds was observed during prokallikrein activation, leading to disulfide-linked two-chain kallikrein.
Conclusions:
- The determined amino acid sequence provides a fundamental basis for understanding human urinary kallikrein structure-function relationships.
- The identification of glycosylation sites and activation cleavage points offers insights into enzyme processing and regulation.