AMINO-ACID MODIFICATION OF PROTEINS IN REGENERATING SCIATIC-NERVES OF RATS

Recent experiments have shown that Arg, Lys, and Leu can be incorporated posttranslationally into proteins of regenerating sciatic nerves of rats. The presentexperiments investigate a mixture of 15 radioactie amino acids to determine if additonalo amino acids can be cojugated posttranslationally to protein of regenerating nerves. Proteins of regenerating sciatic nerves or rats were able to incorporate Arg, Lys, pRO, Val, Ala, Phe, and Ser in relatively large amounts and Asp, Glu, Thr, Gly Ile, His, and Tur in relatively low or undetectable amounts, in the most advanced potion of the regenerating nerves. Two‐Dimensional SDS PAGE showed incorporation of the amono acid mixture into distinct radioactive peaks with moleculer weights in the 80–90 kD, 22–46 kD, and 17 kD ranges with isoelectric point between 5.0 and 7.9. Most of the amono acids were incorporated into proteins in all of the molecular weight ranges. But Ser was incorporated in highest amounts in the 17 kD range. In some cases results indicated that single proteins were modified by several amino acids. While we do not yet know which amino acids modify specidic nerve proteins or the function of the modifications in nerve regenration, these studies demonstrate the participation of some but not all amono acids in posttranslational modification reactions and the selective modification of specific groups of nerve preoteins by these amono acids. Copyright © 1990 Wiley‐Liss, Inc.