Enzymatic methylation of 23-29-kDa bovine retinal rod outer segment membrane proteins. Evidence for methyl ester formation at carboxyl-terminal cysteinyl residues

Journal Article · Sat Aug 05 00:00:00 EDT 1989 · Journal of Biological Chemistry; (USA)

OSTI ID:5478157

Ota, I M; Clarke, S ^[1]

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1. Univ. of California, Los Angeles (USA)

A group of 23-29-kDa polypeptides in the membranes of bovine rod outer segments are substrates for S-adenosylmethionine-dependent methylation reactions. The bulk of the methyl group incorporation is in base-labile ester-like linkages, and does not appear to be due to the widespread D-aspartyl/L-isoaspartyl methyltransferase. To determine the site(s) of methylation, {sup 3}H-methylated proteins separated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate were eluted and digested with papain, leucine aminopeptidase-M, and prolidase. After performic acid oxidation of the digest, a base-labile radioactive material was recovered that coeluted with a synthetic standard of cysteic acid methyl ester upon cation exchange and G-15 gel filtration chromatography, as well as in two thin-layer electrophoresis and two thin-layer chromatography systems. These results provide direct evidence for the methylation of the alpha-carboxyl group of a carboxyl-terminal cysteinyl residue, a modification that has been proposed for the 21-kDa Ha-ras product and other cellular proteins.

• OSTI ID: 5478157
• Journal Information: Journal of Biological Chemistry; (USA), Vol. 264:22; ISSN 0021-9258
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ESTERS
BIOSYNTHESIS
MEMBRANE PROTEINS
METHYLATION
AMINO ACID SEQUENCE
CATTLE
CELL MEMBRANES
CYSTEINE
ELECTROPHORESIS
HYDROLYSIS
ION EXCHANGE
METHYL TRANSFERASES
MOLECULAR WEIGHT
PAPAIN
PEPTIDE HYDROLASES
THIN-LAYER CHROMATOGRAPHY
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINO ACIDS
ANIMALS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHROMATOGRAPHY
DECOMPOSITION
DOMESTIC ANIMALS
ENZYMES
HYDROGEN COMPOUNDS
HYDROLASES
ISOTOPE APPLICATIONS
LYSIS
MAMMALS
MEMBRANES
MOLECULAR STRUCTURE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PROTEINS
RUMINANTS
SEPARATION PROCESSES
SH-PROTEINASES
SOLVOLYSIS
SYNTHESIS
THIOLS
TRANSFERASES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques