Characterization of Changes due to pH Variations in Beta Peptide (25–35) Leading to Alzheimer’s Disease

  • Rethinam SenthilEmail author
  • S. Srividya
  • A. Wilson Aruni
  • Bahri Basaran
  • Jyotsna
  • Rajendran Thirugnanasambandam


The effect of various concentrations of amyloid beta peptide (ABP) in different pH (pH 2, 6, 7, 8, 10) in aging at different time intervals was analysed using various techniques. The pH 7.4 and 8 were compared with other pH solution which indicated that the secondary structure content with high β-sheet conformation is found at pH 7.4 and 8. Phosphate buffer solutions (pH) were detected using CD spectroscopy. The CD spectra of peptide in phosphate buffer (pH 2 and 10) on aging at time intervals were also analysed with the aging of sample (pH 2) on the 10th day. The results showed no major secondary structural changes in the peptide, which was indicative predominant random coil structure. The phosphate buffer pH 6, 7.4, 8 on the 10th day showed the occurrence of crossover point. This same sample smear on slide was mounded and the fibrils were visualized using the light microscope. The percent of viable cell in different pH was detected in MTT (3-(4,5-Dimethyazol-2-yl)-2, 5-diphenyl-tetrazolium bromide) assay using human keratinocyte cell line (HaCaT). Fluorescence spectroscopy was used to study the growth and development of fibrils.


Peptide-Aβ (25–35) Alzheimer’s disease CD spectroscopy Fluorescence spectroscopy MTT assay 


Compliance with Ethical Standards

Conflict of interest

The authors declare that there is no conflict of interest.

Research Involving Human Participants and/or Animals

This article does not contain any studies with human participants or animals performed by any of the authors.

Informed Consent

Informed consent was obtained from all individual participants included in the study.


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© Springer Nature B.V. 2019

Authors and Affiliations

  • Rethinam Senthil
    • 1
    Email author
  • S. Srividya
    • 2
  • A. Wilson Aruni
    • 3
    • 4
  • Bahri Basaran
    • 5
  • Jyotsna
    • 6
  • Rajendran Thirugnanasambandam
    • 6
  1. 1.Department of BiotechnologySathyabama Institute of Science and TechnologyChennaiIndia
  2. 2.Department of BiochemistrySathyabama Dental College & HospitalChennaiIndia
  3. 3.School of Bio & Chemical EngineeringSathyabama Institute of Science and TechnologyChennaiIndia
  4. 4.California University of Science and MedicineSan BernardinoUSA
  5. 5.School of Natural and Applied ScienceEge UniversityBornova/izmirTurkey
  6. 6.Centre for Ocean ResearchCol. Dr. Jeppiaar Research Park, Sathyabama Institute of Science and TechnologyChennaiIndia

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