we have undertaken a comparative study of four aminoacyl-trna synthetases ( glutamyl- , arginyl- , valyl- , and phenylalanyl-trna synthetases ) with subunit sizes ranging from 56,000 to 130,000 daltons in an attempt to correlate the occurrence and extent of the repeats with the length of the polypeptide chain .
C0002529
aminoacyl-trna synthetases
C0031460
phenylalanyl-trna