AMP-DEAMINASES FROM CHICKEN AND RABBIT MUSCLE - PARTIAL PRIMARY SEQUENCES OF HOMOLOGOUS 17-KDA CNBR FRAGMENTS - AUTORECOGNITION BY RABBIT ANTI-[CHICKEN AMPD]

The apparent size (87.5 kDa) of the major polypeptide in freshly isola ted chicken muscle AMP deaminase (AMPD.M) was comparable with that pre dicted from the sequences of the genes for the major muscle isoforms f rom human and rat. The size of the subunit of AMP deaminase from chick en muscle is indistinguishable from that of the rabbit enzyme. The pep tide profiles of cyanogen bromide digests of AMPD.M from chicken and r abbit share a 17-kDa fragment, representing approximately 20% of the i ntact subunits of these enzymes. The first 25 residues of these fragme nts are 88.5% identical; the rabbit and chicken segments are greater t han 92% and 84% identical, respectively, to the sequences predicted fo r residues 310-335 for AMPD.M from human and rat. Polyclonal rabbit an tisera directed against AMPD.M from chicken breast recognize the full- length AMPD.M polypeptides on immunoblots of extracts of both avian an d rabbit muscle, including an antiserum from the rabbit in which the a ntibody was prepared. The 17-kDa fragments, derived by incomplete clea vage of highly conserved internal segments of the deaminase subunit, s hare epitopes involved in the autorecognition of rabbit AMPD.M by rabb it polyclonal antibodies directed against the avian AMPD.M. (C) 1997 E lsevier Science Inc.