| 摘要 |
<p>Alpha subunits of hemoglobin are provided as a novel recombinant di-alpha globin polypeptide comprising the two alpha subunits connected directly via peptide bond or indirectly by a flexible amino-acid or peptide linker. Di-alpha globin may be combined in vivo or in vitro with beta globin and heme to form hemoglobin. Tetrameric human hemoglobin and di-alpha/beta 2 hemoglobin are produced in S. cerevisiae by three types of expression vectors: (1) two separate plasmids containing respectively alpha and beta globin genes expressed in diploid strains; (2) a single plasmid comprising alpha and beta globin genes expressed in either haploid or diploid strains; (3) a single plasmid containing di-alpha and beta globin genes expressed in haploid strains. Tetrameric form or separate subunits can be recovered from the soluble fraction. So, three types of hemoglobin-like molecules can be produced: di-alpha/ two beta, di-beta/ two alpha or di-alpha/ di-beta, with a long half-life.</p> |
