A. Igout et al., PURIFICATION AND BIOCHEMICAL-CHARACTERIZATION OF RECOMBINANT HUMAN PLACENTAL GROWTH-HORMONE PRODUCED IN ESCHERICHIA-COLI, Biochemical journal, 295, 1993, pp. 719-724
The hGH-V (or hGH-2) gene codes for human placental growth hormone (hP
GH). Secretion of hPGH is continuous, in contrast with the pulsed secr
etion of pituitary growth hormone (hGH) which it progressively replace
s in the maternal bloodstream. hGH- V cDNA has previously been cloned
and isolated. Analysis of its nucleotide sequence has revealed a 191-r
esidue protein, hPGH, differing from hGH at 13 positions. The calculat
ed pI is more basic than that of the pituitary hormone. Here we have i
nserted hGH- VcDNA into the pIN-III-ompA3 plasmid in order to produce
hPGH in its native form in Escherichia coli D1210. Expression of hGH-
V cDNA in E. coli is significantly lower than that of hGH cDNA with th
e same expression system. The hPGH produced in E. coli was purified in
quantities sufficient to allow its biochemical and immunochemical cha
racterization. The molecular mass of the protein was determined by ele
ctrospray m.s. The determined mass, 22320 Da, agrees well with the mol
ecular mass calculated from the translated cDNA sequence, assuming the
presence of two disulphide bridges. Having established the technique
for producing hPGH with a primary structure identical to the natural,
non-glycosylated, 22 kDa isoform, we can now plan the full physicochem
ical and pharmaceutical characterization of this new hormonal entity.