Expression and purification of a mutant human growth hormone that is resistant to proteolytic cleavage by thrombin, plasmin and human plasma in vitro

Characterisation of the 5 kDa growth hormone isoform

“…Furthermore, minor constituents of the GH family are generated through alternative splicing (20 and 17.5 kDa), glycosylation (24 kDa), deamidation, homo-and hetero-oligomerisation (Baumann 1999;Lewis et al 2000;Ryther et al 2003). The 22 kDa GH isoform is known to be proteolitically processed in different tissues (Wroblewski et al 1993;Alam et al 1998;Ge et al 2007;Komatsu et al 2007), resulting in a number of isoforms with different biological activity. This fact suggested a pro-hormone role for the 22 kDa isoform (Sinha and Jacobsen 1994;Haro et al 1996;Rowlinson et al 1996).…”

“…A single specific cleavage to generate two contiguous fragments of 5 kDa (AA 1 -43 ) and 17 kDa (AA 44 -191 ) has been reported to yield significant amounts of these isoforms in circulation (Warner et al 1993;Lewis et al 1994Lewis et al , 2000Sinha and Jacobsen 1994;Lopez-Guajardo et al 1998). Another cleavage has been reported at the AA 134 -150 segment (Wroblewski et al 1993;Alam et al 1998;Ge et al 2007;Komatsu et al 2007), although the existence of the resulting fragments has not been confirmed as no specific assay is available. Different biological roles have been reported both for described isoforms and for distinct sequence segments.…”