Biomedical Engineering Reference
In-Depth Information
Previously, Flammang and colleagues (DeMoor et al., 2003) have shown a gel
electrophoresis pattern for the tubule print from H. forskali samples. In this case, a high
background staining was present, and the bands were generally less well defined and more
poorly resolved. In some cases the apparent H. forskali bands had comparable molecular
weights to those observed in the present study. Thus the sharp bands at 95 kDa and 45 kDa
may be similar to the H2 (89 kDa) and H6 (44 kDa) bands, while the diffuse bands at 63 kDa
and 33 kDa may be similar to the H4 (63 kDa) and the H7 (37 kDa) bands, respectively.
3.3 Amino acid analysis
The amino acid compositions determined from amino acid analyses of the 6 principal bands
are given in Table 1. No data were collected for Band H4 as it appeared to be a doublet
(Figure 3). Deamidation during acid hydrolysis means that Asn cannot be distinguished
from Asp, nor can Gln be distinguished from Glu; the two pairs are given as Asx and Glx
respectively. This prevents an estimation of pI for each of these proteins. Hydroxyproline
was not observed in any of the 6 principal bands.
Comparison of the analyses for the various bands did not show signature features for any
particular band, and the compositions were broadly similar for all bands. All of the bands
had high contents of Gly (7.8-16.8 mol%) and Glx (11.6-16.2 mol%) relative to the average for
eukaryotic proteins (6.9 and 9.7 mol%, respectively) (Doolittle, 1986); similarly, DeMoor et
al. (2003) observed high Gly contents (16-22 mol%) for the proteins extracted from H. forskåli.
As noted above, the SDS-PAGE molecular weight data suggests that it is possible that some
bands could be related between the species - H2 and 95 kDa, H6 and 45 kDa and H7 and 33
kDa. Comparison of the amino acid composition data, however, did not show strong
similarities. However, it has been suggested (Flammang and Jangoux, 2004), that the protein
components present in the adhesives differ between species.
H2 H3 H6 H7 H8 H9
Asx 9.7 8.7 12.1 13.1 9.7 15.0
Ser 9.8 11.6 7.0 6.5 10.2 8.0
Glx 16.2 13.3 13.2 12.7 15.0 11.6
Gly 16.1 16.8 7.8 8.1 13.6 10.5
His 1.1 1.0 1.3 ND 0.7 1.3
Arg 3.6 5.2 4.9 4.1 5.5 4.4
Thr 3.9 5.2 5.1 5.0 4.9 4.6
Ala 7.8 7.0 9.2 9.4 6.8 8.0
Pro 3.2 4.9 3.9 3.2 6.3 3.1
Tyr 1.8 2.5 2.4 1.9 3.0 2.4
Val 4.6 5.5 6.4 6.4 5.5 5.7
Met ND 0.4 3.2 3.8 0.4 5.0
Lys 8.8 4.9 8.3 9.4 5.0 7.0
Ile 4.1 3.8 5.6 5.3 3.5 4.8
Leu 7.0 7.0 7.3 8.3 7.5 5.8
Phe 2.4 2.4 2.5 3.0 2.5 2.6
Table 1. Amino acid analysis of individual protein bands after separation by SDS-PAGE.
Results are given as Mol %. ND = Not detected. Trp was not determined.
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