ELECTROSPRAY-IONIZATION STUDIES OF THE INTERACTION OF N,N'-DICYCLOHEXYLCARBODIIMIDE WITH CEROID-LIPOFUSCINOSIS PROTEIN (SUBUNIT-C)

N,N'-dicyclohexylcarbodiimide (DCCD) interacts with isolated ceroid li pofuscinosis protein (CLP), a model for subunit c, The products are (a ) CLP-DCCD adduct (+206 Dal, presumably by addition at Glu-58; (b) ace tyl-CLP-DCCD (+42 Da +206 Dal; (c) acetyl-CLP (+42 Da). Under specific conditions, additional DCCD adducts are formed; CLP-DCCD-DCCD (+206 D a +206 Da) and acetyl-CLP-DCCD-DCCD (+42 Da + 206 Da + 206 Da). Acetyl ation utilises the acetate present in CLP preparations as a buffer and the site is shown to be located within amino acids 1-9 (probably Lys- 7 or N-terminal aspartate), Acetyl-CLP is shown to be the primary prod uct but, in addition, acylation by other fatty acids (myristate, palmi tate, oleate and stearate) can be demonstrated in low acetate concentr ations, Oligomycin is shown to modify some interactions of CLP with DC CD but venturicidin has little or no effect.