E. coli maltodextrin phosphorylase: primary structure and deletion mapping of the C-terminal site.

The complete 796 residue amino acid sequence of maltodextrin phosphorylase was deduced from the E. coli malP nucleotide sequence. The calculated molecular weight of 90,500, including pyridoxal phosphate, is significantly larger than experimentally determined values. Enzymatically active and inactive mutants following deletion or exchange of up to 8 codons (7 amino acids) at the 3' end (C-terminus) confirm the size of the mature native enzyme and disclose the essential functional or structural role of the highly conserved C-terminal region of phosphorylases.