Specific cleavage of N-terminal acetyl-methionine from peptides by rabbit muscle fractions
The authors have investigated the hypothesis that the processing of eukaryotic proteins involves acetylation of the N-terminal Met, followed by removal of the resulting Ac-Met to expose the second amino acid in the sequence. An activity was identified in rabbit muscle extracts that effectively removes Ac-Met from a synthetic peptide I (AcMDETGDTALVA) resembling the N-terminus of actin. The activity is associated with microsomes and free ribosomes, but can be extracted from the ribosomes by treatment with 0.5 M NaCl in the presence of 2 mM Mg/sup + +/; a 200 fold purification is achieved by this differential centrifugation procedure. A number of chemically acetylated (/sup 14/C-Ac) peptides have been tested as substrates using an HPLC assay for liberated /sup 14/C-Ac-Met. The results suggest that the partially purified activity is specific for N-terminal Ac-Met in that other Ac-amino acids (Gly, Ala, Ser, Asp) were not released from similar peptides, including a derivative of peptide I with Met missing and with Ac-Asp as n-terminus. The amino acid in the second position also appears to be involved as a specificity determinant; a peptide Ac-Met-Arg-Phe-Ala was inert and the tripeptide Ac-Met/sub 3/ was a poor substrate. The dipeptide Ac-Met-Glu was also a very poor substrate, while several tripeptides Ac-Met-X-Y, were good substrates, although not as good as the actinlike peptide I.
- Research Organization:
- Univ. of Texas Medical School, Houston
- OSTI ID:
- 5022146
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
METHIONINE
CLEAVAGE
PEPTIDES
ACETYLATION
AMINO ACID SEQUENCE
CARBON 14 COMPOUNDS
CENTRIFUGATION
MICROSOMES
MUSCLES
RABBITS
RIBOSOMES
TRACER TECHNIQUES
ACYLATION
AMINO ACIDS
ANIMALS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
DRUGS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPOTROPIC FACTORS
MAMMALS
MICROSTRUCTURE
MOLECULAR STRUCTURE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOIDS
PROTEINS
SEPARATION PROCESSES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques