Papaya :: Health, Food Safety

Our results of PRSV CP digestibility in gastro-intestinal fluids as well as bioinformatic analysis have shown that the transgene CP protein expressed in Rainbow and cockcrow papaya is not allergenic. The PRSV CP is the major protein expressed in Rainbow papaya on with widely used nptII and GUS plant transformation markers. Here we will talk over about CP protein only as food safety of NPTII and GUS have been communicate elsewhere (24-26). The prediction of allergenicity of novel proteins are based on both bioinformatic and/or experimental approaches (6, 7). Following the bioinformatics analysis, PRSV CP did not show significant comparison to known allergenic proteins based on the criterion of an eight amino group acid identical correspond (27). However, we performed more stringent similarity search criterion of a cardinal amino acid identity match to the query CP sequences which identified only five entries in the SDAP database. Although we identified rattling small numb er of matches to known allergens based on a six amino acid similarity search, numerous reports indicate that the high circumstances of allergenic proteins identified using this criterion are false positives (31, 32) and then in practice does not accurately predict allergenic proteins.A computer based allergenicity prediction report by Kleter and Peijnenburg (28) identified a peptide of six amino acids (EKQKEK) shared by PRSV CP and a proposed allergen ABA-1, a protein of the gracious parasite Ascaris lumbricoides or the pig parasite Ascaris suum. However, as noted previously by Suzuki et al.(29), the PRSV CP match to ABA-1 is not relevant with regards to allergenicity for some(prenominal) reasons 1) the amino acid sequence is not repeated in the cover protein sequence, therefore it will not trigger the IgE response associated with allergens, 2) the ABA-1 proposed allergenic peptide was found to be not inherently allergenic outside the stage setting of other Ascaris proteins ( 30), and 3) it is not among the officially recognized allergens found in the International Union of Immunological Societies (IUIS) allergen database (http//www.allergen.org). An important aspect of assessing potential allergenicity is experimental testing for properties common to allergenic proteins such as stability in simulated gastro-intestinal fluids which include SGF and SIF. SGF was developed to represent the conditions in the human meet (20) and basically consists of the main gastric protease pepsin in low pH medium. Some data suggests that proteins that are susceptible to gastrointestinal digestion are inherently safer than those that are stable especially in terms of allergenicity (5).