Enzyme-linked immunosorbent assay (ELISA) for detection of sulfur-rich protein (SRP) in soybeans (Glycine max L.) and certain other edible plant seeds.
As a result of methionine deficiency, legume proteins are considered to be incomplete, and therefore there is a need to explore ways to improve legume protein amino acid balance. Using rabbit anti-soybean sulfur-rich protein (SRP) polyclonal antibodies (pAb), sensitive immunoassays (nanogram sensitivity) were developed. The immunoassays detected SRP in all soybean seeds and soybean-based commercial samples examined. In addition, the presence of pAb cross-reactive proteins was detected in certain dry beans and oilseeds. The cross-reactive proteins were isolated using purified IgG-based immunoaffinity column chromatography. Biochemical analyses including N-terminal amino acid sequencing and amino acid composition indicated that the cross-reactive proteins were comparable to soybean SRP. The cross-reactive proteins contained methionine (1.6-2.4 residues/100 residues) and cysteine (2.4-3.6 residues/100 residues), which satisfies the FAO/WHO recommended pattern for sulfur amino acids in both adults and children (2-5 years old). The results suggest the presence of constitutive SRPs in several dry beans and oilseeds.
Monaghan
Erin K
EK
Department of Nutrition, Food and Exercise Sciences and Department of Biological Science, Florida State University, Tallahassee, Florida 32306, USA.
Venkatachalam
Mahesh
M
Seavy
Margaret
M
Beyer
Kirsten
K
Sampson
Hugh A
HA
Roux
Kenneth H
KH
Sathe
Shridhar K
SK
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000906:Antibodies; D000918:Antibody Specificity; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000032:analysis / Q000737:chemistry; D011817:Rabbits; D012639:Seeds / Q000737:chemistry*; D030262:Soybean Proteins / Q000032:analysis* / Q000737:chemistry
D000596:Amino Acids; D000906:Antibodies; D010940:Plant Proteins; C085202:SE60 protein, Glycine max; D030262:Soybean Proteins