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Amino acid sequences of the human kidney cathepsins H and L
A Ritonja1, T Popović, M Kotnik
1Department of Biochemistry, J. Stefan Institute, Ljubljana, Yugoslavia.
Insights
Researchers determined the amino acid sequences of human kidney cathepsin H and cathepsin L. These cysteine proteinases show significant sequence homology to cathepsin B and other papain superfamily members.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- Cathepsins are key cysteine proteases involved in various cellular processes.
- Understanding the specific sequences of human kidney cathepsins is crucial for their functional and structural characterization.
- Human kidney cathepsin H (EC 3.4.22.16) and cathepsin L (EC 3.4.22.15) are important enzymes with roles in protein degradation and processing.
Purpose of the Study:
- To determine the complete amino acid sequences of human kidney cathepsin H and cathepsin L.
- To provide foundational data for further studies on the structure-function relationships of these enzymes.
- To compare the sequences with related cysteine proteinases.
Main Methods:
- Amino acid sequencing of isolated enzyme chains (light, heavy, mini) and peptides.
- Cyanogen bromide cleavage of the single-chain form of cathepsin H.
- Deduction of cathepsin L sequence from N-terminal and cyanogen bromide fragment sequences.
- Sequence alignment with known cathepsin sequences from other species.
Main Results:
- The complete amino acid sequence of human kidney cathepsin H (230 residues, Mr 25116) was determined.
- The complete amino acid sequence of human kidney cathepsin L (217 residues, Mr 23720) was elucidated.
- Both cathepsins H and L demonstrated high sequence homology to cathepsin B and other cysteine proteinases within the papain superfamily.
Conclusions:
- The determined sequences provide essential molecular information for human kidney cathepsin H and L.
- The high sequence homology suggests conserved structural and functional features within the papain superfamily of cysteine proteinases.
- These findings contribute to a deeper understanding of human cathepsin biology and their potential roles in health and disease.
Abstract:
The complete amino acid sequences of human kidney cathepsin H (EC 3.4.22.16) and human kidney cathepsin L (EC 3.4.22.15) were determined. Cathepsin H contains 230 residues and has an Mr of 25116. The sequence was obtained by sequencing the light, heavy and mini chain and the peptides produced by cyanogen bromide cleavage of the single-chain form of the enzyme. The glycosylated mini chain is a proteolytic fragment of the propeptide of cathepsin H. Human cathepsin L has 217 amino acid residues and an Mr of 23720. Its amino acid sequence was deduced from N-terminal sequences of the heavy and light chains and from the sequences of cyanogen bromide fragments of the heavy chain. The fragments were aligned by comparison with known sequences of cathepsins H and L from other species. Cathepsins H and L exhibit a high degree of sequence homology to cathepsin B (EC 3.4.22.1) and other cysteine proteinases of the papain superfamily.