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Antioxidants play an important role in animal and plant life owing to their involvement in complex metabolic and signaling mechanisms, hence uncovering the genetic basis associated with antioxidant activity is very important for the development of improved varieties. Here, a total of 182 common bean ( Phaseolus vulgaris ) landraces and six commercial cultivars collected from 19 provinces of Turkey were evaluated for seed antioxidant activity under four environments and two locations. Antioxidant activity was measured using ABTS radical scavenging capacity and mean antioxidant activity in common bean landraces was 20.03 µmol TE/g. Analysis of variance reflected that genotype by environment interaction was statistically non-significant and heritability analysis showed higher heritability of antioxidant activity. Variations in seed color were observed, and a higher antioxidant activity was present in seeds having colored seed as compared to those having white seeds. A negative correlation was found between white-colored seeds and antioxidant activity. A total of 7900 DArTseq markers were used to explore the population structure that grouped the studied germplasm into two sub-populations on the basis of their geographical origins and trolox equivalent antioxidant capacity contents. Mean linkage disequilibrium (LD) was 54%, and mean LD decay was 1.15 Mb. Mixed linear model i.e., the Q + K model demonstrated that four DArTseq markers had significant association ( p < 0.01) for antioxidant activity. Three of these markers were present on chromosome Pv07, while the fourth marker was located on chromosome Pv03. Among the identified markers, DArT-3369938 marker showed maximum (14.61%) variation. A total of four putative candidate genes were predicted from sequences reflecting homology to identified DArTseq markers. This is a pioneering study involving the identification of association for antioxidant activity in common bean seeds. We envisage that this study will be very helpful for global common bean breeding community in order to develop cultivars with higher antioxidant activity.

The specific enzymatic activity of four different aminopeptidases (aminopeptidase N, leucine aminopeptidase, aminopeptidase A and aminopeptidase B) in vaginal homogenates from rabbit, rat, guinea-pig, sheep and humans was compared. The purpose of the study was to find an appropriate animal model that can be used in degradation studies of protein and peptide drugs. Different substrates were used as the relative specific substrates for the determination of aminopeptidase enzymatic activity: 4-methoxy-2-naphthylamide of L-alanine for aminopeptidase N, 4-methoxy-2-naphthylamide of L-leucine for leucine aminopeptidase, 4-methoxy-2-naphthylamide of L-glutamic acid for aminopeptidase A and 4-methoxy-2-naphthylamide of L-arginine for aminopeptidase B. The vaginal aminopeptidase enzymatic activity of different species was determined spectrofluorometrically. The inhibition of aminopeptidase activity in the presence of bestatin and puromycin inhibitors was also investigated. The results showed the presence of aminopeptidase enzymatic activity in all vaginal homogenates in the order: sheep > guinea-pig > rabbit > or = human > or = rat. Based on the results of the hydrolysis and inhibition of the 4-methoxy-2-naphthylamide substrates, it was difficult to have an exact decision on the aminopeptidase type in the vaginal homogenates from the species studied. It was found that the aminopeptidase activity in rat, rabbit and humans was not statistically different. Therefore, we suggest that rats and rabbits could be used as model animals for vaginal enzymatic activity studies and for determination of the degradation of protein and peptide drugs in the vagina.