Characterization and purification of β−secretase inhibitory peptides fraction from sea cucumber (Holothuria spinifera) enzymatic hydrolysates

• Published in: Process biochemistry (1991) Vol. 111; pp. 86 - 96
• Main Authors: Rathnayake, Anuruddhika Udayangani, Abuine, Racheal, Palanisamy, Subramanian, Lee, Jung Kwon, Byun, Hee-Guk
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01.12.2021; Elsevier BV
• Subjects: Alzheimer's disease; Amino acids; Amyloid precursor protein; Biological activity; c-Jun protein; Cognitive ability; Food industry; Food sources; Functional foods & nutraceuticals; Glycine; High-performance liquid chromatography; Holothuria spinifera; Hydrolysate; Hydrolysates; Hypotheses; JNK protein; Kinases; Liquid chromatography; Neuroblasts; Neurodegeneration; Neurodegenerative diseases; Older people; Oxidative stress; Peptides; Phosphorylation; Precursors; Protein kinase; Protein purification; Proteins; Public health; Secretase; Transcription factors; Trypsin; β-secretase; Holothuria spinifera; β-secretase; Alzheimer’s disease; Peptides; Hydrolysate
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2021.10.007

[Display omitted] •The bioactive peptides were separated from sea cucumber Holothuria spinifera.•Glycine was the most abundant amino acid in the dried H. spinifera.•Trypsin hydrolysate showed the highest β-secretase inhibitory activity.•The effect of active fraction (HPLC-F3) was tested in SH-SY5Y neuroblastoma cells.•HPLC-F3 reduced BACE, Aβ, sAPPβ, p-p38, and p-JNK protein expression levels. Alzheimer’s disease (AD) is widely known as a progressive neurodegenerative disorder, mainly found in the elderly population. Progressive neurodegeneration in AD can lead to cognitive functional and behavioral alterations, thus affecting public health. Based on the amyloid cascade hypothesis, enzymatic cleavage of amyloid precursor protein (APP) by β-secretase and the formation of amyloid-beta (Aβ) peptides lead to neuron cell degradation. In this study, we focused on this hypothesis and investigated bioactivities of dried Holothuria spinifera enzymatic hydrolysates. Dried H. spinifera contained 79.77 % protein with glycine being the most abundant amino acid (178.89 g/kg). Trypsin hydrolysate of H. spinifera exhibited the highest β-secretase inhibitory activity with an IC50 value of 81.94 μg/mL. RP-HPLC produced an active fraction (HPLC-F3) containing four bioactive peptides (YPIEHGIVTNWDDM*EK, IEELEEEIEAER, EYVEETTGDEYVSLK, YPIEHGIVTNWDDMEK). The predominant peptide presented in HPLC-F3 was IEELEEEIEAER. Effects of HPLC-F3 against SH-SY5Y neuroblastoma cells were tested. HPLC-F3 reduced cellular levels of β-secretase enzyme, Aβ, and soluble amyloid precursor protein beta (sAPPβ) proteins. HPLC-F3 also protected SH-SY5Y cells from oxidative stress by decreasing phosphorylation of c-Jun N-terminal kinases and p38 mitogen-activated protein kinases. Results of this study suggest that H. spinifera is a potential source for functional foods and biomedicine industries.