attached
Seaweeds are well recognized as a potential protein
source. The edible green seaweed, Ulva sp., is abundant in the
Brittany Coast, France. This study examined the extraction of
proteins and glycoproteins from this seaweed. Four different
extraction procedures (Procedure 1: deionized water, DW;
Procedure 2: lysis solution 1 (LS1) containing 8 M urea, 2%
Tween 20, 2% Triton X-100, 30 mM dithiothreitol, and 1%
polyvinylpyrolidine; Procedure 3: lysis solution 2 (LS2) containing 50 mM Tris-HCl buffer pH 8, 10 mM EDTA, 2 mM
Na2S2O5, and 1% Triton X-100; Procedure 4: 50 mM TrisHCl buffer, pH 8) were applied to extract proteins from Ulva
sp. in Brittany. The protein contents (%, dry basis) in the
above extracts from Procedures 1–4 were 4.36 ± 0.21,
11.88 ± 0.23, 10.34 ± 0.35, and 3.58 ± 0.48, respectively.
Moreover, electrophoresis (SDS-PAGE) revealed that the protein profile varies with season. Three glycoprotein-rich fractions, namely, GP-1 (from Procedure GP1), GP-2-DA, and
GP-2-DS (from Procedure GP2), were extracted from Ulva
sp. GP-1 and GP-2-DA fractions have a higher protein content
than neutral sugars, while GP-2-DS contains a higher amount
of neutral sugars than proteins. Matrix-assisted laser desorption ionization-time of flight/mass spectrometry (MALDITOF/MS) technique was applied to further proteomic analysis
of each glycoprotein-rich fraction. GP-2-DS was hydrolyzed
with protease enzyme to confirm the availability of proteins,
and interestingly, the particular hydrolysate shows no
original peaks in the MALDI-TOF/MS analysis. All three
glycoprotein-rich fractions show no cytotoxicity in Vero cells
at the tested concentration (500 mg dw mL−1
). Collectively,
these results revealed that the extractable protein content and
protein profile of Ulva sp. differ according to the extraction
liquid system and the season. The utilization and value addition of proliferative Ulva sp. in Brittany as a protein source is
promising but needs to consider the seasonal change of the
protein profile.
