Cruor, the main component responsible for the red color of blood in mammals, contains 90% hemoglobin, a protein that is considered a rich source of bioactive peptides. The aim of the present study is to evaluate the potential of human hemoglobin as a source of bioactive peptides, compared to bovine hemoglobin, which has been widely studied in recent years. More specifically, the study focused on neokyotorphin, a natural antimicrobial peptide and meat preservative, which corresponds to the α137-141 fragment of bovine hemoglobin produced by enzymatic hydrolysis. Firstly, the results of the in-silico analysis showed that the two types of hemoglobin have a high similarity for the α and β chains (identities of 88% and 91%, respectively). Secondly, both types of hemoglobin were subjected to similar enzymatic hydrolysis conditions, which showed that the hydrolysis of human hemoglobin followed the same reaction mechanism as the hydrolysis of bovine hemoglobin, the 'Zipper' mechanism. The hydrolysis conditions (23°C, pH 3.5) made it possible to obtain α137-141 in significant quantities to allow for significant valorization from an industrial point of view. The hydrolyses were able to take place at high initial substrate concentrations, allowing for faster and more efficient processing of the co-product in the same amount of time, with over 65% of this production achieved in just 30 min. Increasing the substrate concentration (from 1% to 10% (w/v)) resulted in a proportional increase in α137-141 production. Regardless of the concentrations tested, the kinetic pattern remained similar. Finally, the results of the mass spectrometry analysis revealed the presence of several bioactive peptides in cattle and humans. Although some were known before, new bioactive peptides were discovered in human hemoglobin, such as four antibacterial peptides (α37-46 PTTKTYFPHF; α36-45 FPTTKTYFPH; α137-141 TSKYR; α133-141 STVLTSKYR), four opioid peptides (α137-141 TSKYR; β31-40 LVVYPWTQRF; β31-37 LVVYPWT), an ACE inhibitor (β129-135 KVVAGVA), an anticancer agent (β33-39 VVYPWTQ) and an antioxidant (α137-141 TSKYR). These peptides have never been found in human hemoglobin before, according to our knowledge. These results highlight the potential of human hemoglobin as a source of bioactive peptides useful for the food or pharmaceutical industry.

Enzymatic hydrolysis of bovine and human hemoglobin yields a diversity of bioactive peptides, some of which are recognized for their antimicrobial properties. Certain small antimicrobial and anticancer peptides target protein synthesis inhibition. This study aims to produce bioactive peptides through enzymatic hemoglobin hydrolysis and evaluate their effects on cell growth inhibition, potentially serving as candidates for biological anticancer drugs. Rapid screening of candidate anticancer peptides derived from enzymatic hydrolysis of bovine and human hemoglobin was conducted using the Lepidium sativum radicle growth technique. The results demonstrate that: 1) the degree of hydrolysis (DH) significantly influences the production of bioactive peptides. DH levels of 3-10% yield considerably stronger radicle growth inhibition compared to DH 0 (native hemoglobin form), exhibiting three to four times greater intensity. 2) Certain peptide fractions from bovine hemoglobin exhibit higher activity than those from human hemoglobin. 3) The structural characteristics of peptides play a crucial role in the observed biological effects. 4) The α137-141 peptide is the most active among the fractions obtained from bovine (IC₅₀ = 29 ± 1 µg/mL) and human hemoglobin (IC₅₀ = 48 ± 2 µg/mL), standing out 10 to 15 times more potent than other hemoglobin fractions. In conclusion, these findings affirm the bioactivity of peptide fractions obtained from bovine and human hemoglobin. The study highlights how enzymatic hydrolysis of bovine and human hemoglobin can yield peptides that inhibit protein synthesis. Ultimately, these results suggest the feasibility of obtaining candidate peptides for biological anticancer drugs from both human and bovine hemoglobin sources. These scientific advances show new hope in the fight against cancer which affects a large number of people around the world.

This study focuses on the enzymatic hydrolysis of hemoglobin, the main component of cruor that gives blood its red color in mammals. The antibacterial and antioxidant potential of human hemoglobin hydrolysates were evaluated in comparison to bovine hemoglobin. The results showed strong antimicrobial activity of the peptide hydrolysates against six bacterial strains, independent of the initial substrate concentration level. The hydrolysates also showed strong antioxidant activity measured by four different tests. In addition, the antimicrobial and antioxidant activity of the human and bovine hemoglobin hydrolysates showed little or no significant difference, with only the concentration level being the determining factor in their activity. The results of the mass spectrometry study showed the presence of a number of bioactive peptides, the majority of which have characteristics similar to those mentioned in the literature. New bioactive peptides were also identified in human hemoglobin, such as antibacterial peptides PTTKTYFPHF (α37-46), FPTTKTYFPH (α36-45), TSKYR (α137-141) and STVLTSKYR (α133-141), as well as an antioxidant TSKYR (α137-141). According to these findings, human hemoglobin represents a promising source of bioactive peptides beneficial to the food or pharmaceutical industries.