Abstract
1. Methionyl-t-RNA synthetase (where t-RNA denotes `soluble' or transfer RNA) has been purified to apparent homogeneity from a ribonuclease I-free strain of Escherichia coli. Polyacrylamide-gel electrophoresis of the final product revealed a single band. The purified enzyme catalyses the exchange of 450μmoles of pyrophosphate into ATP/mg. in 15min. at 37°. 2. Methionyl-t-RNA synthetase is specific for the l-isomer of methionine, but appears to catalyse the methionylation of two distinct species of t-RNA, both of which are specific for methionine, but only one of which may be subsequently formylated. 3. The Michaelis constant for l-methionine is 2×10−4m in the ATP–PPi exchange assay and 2×10−5m for the acylation of t-RNA. 4. Gel filtration of both crude and highly purified preparations of methionyl-t-RNA synthetase on Sephadex G-200 indicates that the active species of enzyme has a molecular weight of about 190000. The amino acid composition of the enzyme is similar to those reported for the isoleucine and tyrosine enzymes from E. coli.
Full text
PDF![17](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f76b/1198268/362de8536467/biochemj00738-0025.png)
![18](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f76b/1198268/02a5cef0ba74/biochemj00738-0026.png)
![19](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f76b/1198268/fb1bfc7281e4/biochemj00738-0027.png)
![20](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f76b/1198268/534822541a63/biochemj00738-0028.png)
![21](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f76b/1198268/c5edadc8cd74/biochemj00738-0029.png)
![22](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f76b/1198268/2d30fc8504cb/biochemj00738-0030.png)
![23](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f76b/1198268/d9d970ca7456/biochemj00738-0031.png)
![24](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f76b/1198268/d4e0760ea736/biochemj00738-0032.png)
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Adams J. M., Capecchi M. R. N-formylmethionyl-sRNA as the initiator of protein synthesis. Proc Natl Acad Sci U S A. 1966 Jan;55(1):147–155. doi: 10.1073/pnas.55.1.147. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Andrews P. The gel-filtration behaviour of proteins related to their molecular weights over a wide range. Biochem J. 1965 Sep;96(3):595–606. doi: 10.1042/bj0960595. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BEAVEN G. H., HOLIDAY E. R. Ultraviolet absorption spectra of proteins and amino acids. Adv Protein Chem. 1952;7:319–386. doi: 10.1016/s0065-3233(08)60022-4. [DOI] [PubMed] [Google Scholar]
- Baldwin A. N., Berg P. Purification and properties of isoleucyl ribonucleic acid synthetase from Escherichia coli. J Biol Chem. 1966 Feb 25;241(4):831–838. [PubMed] [Google Scholar]
- CRESTFIELD A. M., STEIN W. H., MOORE S. On the preparation of bovine pancreatic ribonuclease A. J Biol Chem. 1963 Feb;238:618–621. [PubMed] [Google Scholar]
- Calendar R., Berg P. Purification and physical characterization of tyrosyl ribonucleic acid synthetases from Escherichia coli and Bacillus subtilis. Biochemistry. 1966 May;5(5):1681–1690. doi: 10.1021/bi00869a033. [DOI] [PubMed] [Google Scholar]
- HJERTEN S., LEVIN O., TISELIUS A. Protein chromatography on calcium phosphate columns. Arch Biochem Biophys. 1956 Nov;65(1):132–155. doi: 10.1016/0003-9861(56)90183-7. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- MARCKER K., SANGER F. N-FORMYL-METHIONYL-S-RNA. J Mol Biol. 1964 Jun;8:835–840. doi: 10.1016/s0022-2836(64)80164-9. [DOI] [PubMed] [Google Scholar]
- MOUSTAFA E. PURIFICATION AND PROPERTIES OF LYSYL- AND METHIONYL-SOLUBLE RIBONUCLEIC ACID SYNTHETASES FROM WHEAT GERM. Biochim Biophys Acta. 1964 Nov 15;91:421–426. doi: 10.1016/0926-6550(64)90072-6. [DOI] [PubMed] [Google Scholar]
- SCHWEET R. S., ALLEN E. H. Purification and properties of tyrosine-activating enzyme of hog pancreas. J Biol Chem. 1958 Nov;233(5):1104–1108. [PubMed] [Google Scholar]
- Stern R., Mehler A. H. Lysyl-sRNA synthetase from Escherichia coli. Biochem Z. 1965 Aug 19;342(4):400–409. [PubMed] [Google Scholar]
- WEBSTER G. C. Isolation of an alanine-activating enzyme from pig liver. Biochim Biophys Acta. 1961 Apr 29;49:141–152. doi: 10.1016/0006-3002(61)90877-0. [DOI] [PubMed] [Google Scholar]
- Webster R. E., Engelhardt D. L., Zinder N. D. In vitro protein synthesis: chain initiation. Proc Natl Acad Sci U S A. 1966 Jan;55(1):155–161. doi: 10.1073/pnas.55.1.155. [DOI] [PMC free article] [PubMed] [Google Scholar]