Abstract
The tryptophan-containing peptides were isolated from the chymotryptic digest of S-carboxymethylated papain. Residue 175, which is strongly hydrogen-bonded to the active-site histidine residue in the tertiary structure of papain, is asparagine, confirming the work of Kimmel, Rogers & Smith (1965). Its function is probably to maintain the orientation and tautomeric state of the imidazole ring of histidine-159. The amino acid sequence predicted from the electron-density map of papain for residues 64–68 was confirmed, but residue 64 is asparagine, not aspartic acid. This residue, which is about 10 Å from the thiol group of the active-site cysteine-25, cannot therefore be a site of electrostatic attraction for substrates of basic amino acids.
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Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Alden R. A., Wright C. S., Kraut J. A hydrogen-bond network at the active site of subtilisin BPN'. Philos Trans R Soc Lond B Biol Sci. 1970 Feb 12;257(813):119–124. doi: 10.1098/rstb.1970.0014. [DOI] [PubMed] [Google Scholar]
- Blow D. M., Birktoft J. J., Hartley B. S. Role of a buried acid group in the mechanism of action of chymotrypsin. Nature. 1969 Jan 25;221(5178):337–340. doi: 10.1038/221337a0. [DOI] [PubMed] [Google Scholar]
- Drenth J., Jansonius J. N., Koekoek R., Sluyterman L. A., Wolthers B. G. IV. Cysteine proteinases. The structure of the papain molecule. Philos Trans R Soc Lond B Biol Sci. 1970 Feb 12;257(813):231–236. doi: 10.1098/rstb.1970.0022. [DOI] [PubMed] [Google Scholar]
- Drenth J., Jansonius J. N., Koekoek R., Swen H. M., Wolthers B. G. Structure of papain. Nature. 1968 Jun 8;218(5145):929–932. doi: 10.1038/218929a0. [DOI] [PubMed] [Google Scholar]
- Husain S. S., Lowe G. Completion of the amino acid sequence of papain. Biochem J. 1969 Sep;114(2):279–288. doi: 10.1042/bj1140279. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Husain S. S., Lowe G. Evidence for histidine in the active site of papain. Biochem J. 1968 Aug;108(5):855–859. doi: 10.1042/bj1080855. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Husain S. S., Lowe G. The location of the active-site histidine residue in the primary sequence of papain. Biochem J. 1968 Aug;108(5):861–866. doi: 10.1042/bj1080861. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KIMMEL J. R., ROGERS H. J., SMITH E. L. TRYPTIC DIGEST OF PAPAIN. II. ISOLATION AND SEQUENCES OF PEPTIDES FROM THE CARBOXYMETHYLATED PROTEIN. J Biol Chem. 1965 Jan;240:266–280. [PubMed] [Google Scholar]
- KIMMEL J. R., SMITH E. L. Crystalline papain. I. Preparation, specificity, and activation. J Biol Chem. 1954 Apr;207(2):515–531. [PubMed] [Google Scholar]
- LIGHT A., FRATER R., KIMMEL J. R., SMITH E. L. CURRENT STATUS OF THE STRUCTURE OF PAPAIN: THE LINEAR SEQUENCE, ACTIVE SULFHYDRYL GROUP, AND THE DISULFIDE BRIDGES. Proc Natl Acad Sci U S A. 1964 Nov;52:1276–1283. doi: 10.1073/pnas.52.5.1276. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Matthews B. W., Sigler P. B., Henderson R., Blow D. M. Three-dimensional structure of tosyl-alpha-chymotrypsin. Nature. 1967 May 13;214(5089):652–656. doi: 10.1038/214652a0. [DOI] [PubMed] [Google Scholar]
- Offord R. E. Electrophoretic mobilities of peptides on paper and their use in the determination of amide groups. Nature. 1966 Aug 6;211(5049):591–593. doi: 10.1038/211591a0. [DOI] [PubMed] [Google Scholar]
- Sigler P. B., Blow D. M., Matthews B. W., Henderson R. Structure of crystalline -chymotrypsin. II. A preliminary report including a hypothesis for the activation mechanism. J Mol Biol. 1968 Jul 14;35(1):143–164. doi: 10.1016/s0022-2836(68)80043-9. [DOI] [PubMed] [Google Scholar]
- THOMSON A. R., MILES B. J. ION-EXCHANGE CHROMATOGRAPHY OF AMINO-ACIDS: IMPROVEMENTS IN THE SINGLE COLUMN SYSTEM. Nature. 1964 Aug 1;203:483–484. doi: 10.1038/203483a0. [DOI] [PubMed] [Google Scholar]
- Wang J. H., Parker L. Pretransition-state protonation and the rate of chymotrypsin catalysis. Proc Natl Acad Sci U S A. 1967 Dec;58(6):2451–2454. doi: 10.1073/pnas.58.6.2451. [DOI] [PMC free article] [PubMed] [Google Scholar]