1&3: hGH-sc(Fc)2 2&4: hGH-Fc anti-Fc anti-hGH 1 2 3 4 1 2 3 4 Supplementary Data Figure 1. Identification of hGH fusion proteins. Both anti-hIgG (Fc specific) antibody and anti-hGH antibody recognized the target bands on the Western blot membrane of purified samples of hGH-sc(Fc)2 and hGH-Fc.

Supplementary Data Figure 2 Supplementary Data Figure 2. The hGH-Fc and hGH-sc(Fc)2 fusion proteins were analyzed for degradation following storage in PBS at 4 ˚C by SDS-PAGE/Coomassie blue staining. Sample identities are listed in the table blow. Supplementary Data Table 1. Stability of hGH-sc(Fc)2 and hGH-Fc in PBS at 4 ˚C Sample Lane # Gel A Gel B Gel C Sample Days of storage 1 hGH-Fc 7 hGH-sc(Fc)2 6 2 17 16 3 28 27 4 35 34 5 47 48 59 60 73 74 8 88 89

Mannitol phosphate buffer Supplementary Data Table 2. Stability of hGH-sc(Fc)2 Storage Conditions Residual Activity* Duration Temp. Buffer 0 month -- PBS 1 month 4 ˚C 106% 2 months 94% -80 ˚C 74% Mannitol phosphate buffer *Activity was determined by the Nb2 cell proliferation assay and the ED50 values were compared.

Supplementary Data Figure 3. Characterization of hIgG1-Fc Supplementary Data Figure 3. Characterization of hIgG1-Fc. Conditioned media containing hIgG1-Fc from transiently transfected HEK293 cells was collected and (A) analyzed by non‐reducing SDS‐PAGE and (B) reducing SDS-PAGE followed by Western blot probed with goat anti‐hIgG Fc specific antibody (1:3000 dilution), or (C) purified by Protein A‐Sepharose® 4B followed by native gel with Coomassie blue staining. 55- 70- 25- 35- A B C

1 2 1: hGH-sc(Fc)2 2: sc(Fc)2-hGH 95 kDa- 72 kDa- 55 kDa- 43 kDa- Supplementary Data Figure 4. Expression test of hGH fusion proteins. Anti-hGH antibody recognized the target bands on the Western blot membrane of the expression samples of hGH-sc(Fc)2 and sc(Fc)2-hGH. The expression level of hGH-sc(Fc)2 was about 3-fold higher than that of sc(Fc)2-hGH. 1: hGH-sc(Fc)2 2: sc(Fc)2-hGH 1 2 95 kDa- 72 kDa- 55 kDa- 43 kDa- 34 kDa- 26 kDa-