부산대학교 도서관

Bacterial alkaline phosphatases (APases), except those isolated from Bacillus licheniformis, are approximately 45‐kDa proteins while eucaryotic alkaline phosphatases are 60 kDa. To answer the question of whether the apparent 60‐kDa alkaline phosphatase from Bacillus licheniformisaccurately reflected the size of the protein, the entire gene was analyzed. DNA sequence analysis of the alkaline phosphatase I (APaseI) gene of B. licheniformisMC14 indicated that the gene could code for a 60‐kDa protein of 553 amino acids. The deduced protein sequence of APaseI showed about 32% identity to those of B. subtilisAPase III and IV and had apparent sequence homologies in the core structure and active sites that are conserved among APases of various sources. The extra carboxy‐terminal sequence of APaseI, which made the enzyme bigger than other procaryotic APases, was not homologous to those of eucaryotic APases. The amino acid composition of APaseI was most similar to that of salt‐dependent APase among the isozymes of B. licheniformisMC14. Another open reading frame of 261 amino acids was present 142 nucleotide upstream of the APaseI gene and its predicted amino acid sequence showed 68% identity to that of glucose dehydrogenase of B. megaterium.