title: Sequence homology between human alpha 1-antichymotrypsin, alpha 1-antitrypsin, and antithrombin III.
abstract: alpha 1-Antichymotrypsin mRNA was isolated by specific polysome immunoprecipitation from turpentine-treated baboon liver. The highly enriched mRNA was used for synthesis and cloning of the corresponding cDNA. Baboon alpha 1-antichymotrypsin cDNA clones were identified by hybrid-selected translation, and the insert DNA fragment from one of the putative clones was used as a probe to screen a human liver cDNA library comprised of 40 000 independent transformants. One of the human cDNA clones was unambiguously identified to contain alpha 1-antichymotrypsin DNA sequences by comparison of its 5'-terminal nucleotide sequence with the N-terminal amino acid sequence of the protein. This cDNA clone, designated phACT235, contains 1524 base pairs of human DNA, which was sequenced in its entirety. The inserted DNA codes for a 25 amino acid signal peptide sequence and the entire mature alpha 1-antichymotrypsin of 408 amino acid residues. Comparison of the amino acid sequence of alpha 1-antichymotrypsin with that of the human alpha 1-antitrypsin has revealed a homology level similar to that between chymotrypsin and trypsin.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000990:Antithrombin III; D001483:Base Sequence; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002621:Chemistry; D002918:Chymotrypsin / Q000037:antagonists & inhibitors*; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis; D006801:Humans; D007120:Immunochemistry; D010215:Papio; D011132:Polyribosomes / Q000032:analysis; D000514:alpha 1-Antichymotrypsin; D000515:alpha 1-Antitrypsin
chemical_list: D000514:alpha 1-Antichymotrypsin; D000515:alpha 1-Antitrypsin; D000990:Antithrombin III; D004247:DNA; D002918:Chymotrypsin