“…Before the NMR analysis, the samples were lyophilized and resuspended in deuterium oxide. Figure 1 shows the NMR proton spectrum of a human seminal plasma sample in D 2 O solution acquired at 600 MHz and 298 K. The assignment reported in detail in Table 1 was obtained by bidimensional NMR spectra (data not shown) according to previous papers [Gupta et al, 2011a,b;Averna et al 2005;Gupta et al 2013;Lynch et al 1994;Patel et al 1999;Seaglen et al 1995]. The enlarged signals at 7.18, 6.92, 6.89, and 6.75 ppm, marked with an asterisk in Figure 1, in the region of aromatic protons of phenylalanine, tyrosine, and histidine, show a characteristic line width broadening of proton resonances.…”