Peptide name : GM15

Source/Organism : Not found

Linear/Cyclic : Linear

Chirality : L

Peptide length: 15

C-terminal modification: Linear

N-terminal modification : Not found

Non-natural peptide information: None

Assay type : MTT assay

Assay time : 24h

Activity : Not found

Cell line : KB

Cancer type : Oral cancer

Other activity : Not found

Amino acid composition bar chart :

Molecular mass : 1561.9776 Dalton

Aliphatic index : 0.906

Instability index : 3.3667

Hydrophobicity (GRAVY) : 0.52

Isoelectric point : 9.5039

Charge (pH 7) : 2.7383

Aromaticity : 0

Molar extinction coefficient (cysteine, cystine): (0, 125)

Hydrophobic/hydrophilic ratio : 2.75

hydrophobic moment : -0.266

Missing amino acid : W,H,Q,E,F,S,D,Y,N,A

Most occurring amino acid : G

Most occurring amino acid frequency : 3

Least occurring amino acid : T

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.2, 0.2, 0.3)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@@H](NC(=O)[C@H](CS)NC(=O)[C@@H](NC(=O)CNC(=O)CN)[C@@H](C)O)C(C)C)C(=O)N[C@@H](CCCNC(=N)N)C(=O)NCC(=O)N[C@@H](CS)C(=O)N[C@H](C(=O)N1CCC[C@H]1C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCSC)C(=O)O)C(C)C

1 : Sannasimuthu A, et al. Design and characterization of a novel Arthrospira platensis glutathione oxido-reductase-derived antioxidant peptide GM15 and its potent anti-cancer activity via caspase-9 mediated apoptosis in oral cancer cells. Free Radic Biol Med. 2019; 135:198-209. doi: 10.1016/j.freeradbiomed.2019.03.006

Paper title : Design and characterization of a novel Arthrospira platensis glutathione oxido-reductase-derived antioxidant peptide GM15 and its potent anti-cancer activity via caspase-9 mediated apoptosis in oral cancer cells.

Doi : https://doi.org/10.1016/j.freeradbiomed.2019.03.006

Abstract : Glutathione oxido-reductase (GR) is a primary antioxidant enzyme of most living forms which protects the cells from oxidative metabolism by reducing glutathione (GSH) from its oxidized form (GSSG). Although the antioxidant role of the enzyme is well characterized, the specific role of conserved N' peptide sequence in antioxidant mechanism remains unclear. In this study, we have identified an RNA sequence encoding GR enzyme from spirulina, Arthrospira platensis (Ap) and the changes in its gene expression profile was analysed during H₂O₂ stress. Results showed that H₂O₂ (10 mM) stimulated the expression of ApGR throughout the timeline of study (0, 5, 10, 15 and 20 days) with highest expression at 5th day post-exposure which confirmed the antioxidant role of ApGR in spirulina during H₂O₂ induced oxidative stress. A dithiol containing short antioxidant peptide, 39GGTCVIRGCVPKKLM53 (GM15) from ApGR was predicted and its radicals (superoxide and hydroxyl radical) scavenging potential was confirmed by in vitro cell-free assays. GM15 (12.5 μM) reduced the intracellular generalized oxidative stress level, as measured using DCFDA assay in H₂O₂ exposed leucocytes without affecting any of the cellular population. Further, the biomedical application of the radical scavenging property of GM15 was validated in oral carcinoma (KB) cells where GM15 exhibited significant cytotoxicity. Also, GM15 exhibited heterogenous effects on intracellular oxidative stress level in KB cells: at lower concentration (6.25 μM), the peptide reduced oxidative stress whereas, at higher concentration (25 μM) it increased the intensity of oxidative stress. GM15 (25 μM) induced caspase-9 mediated apoptosis in KB cells along with membrane disruption and DNA degradation which are confirmed by propidium iodide (PI) internalization and comet assays, respectively. Overall, the study shows that GM15 peptide i) scavenges superoxide, hydroxyl radicals, and influences intracellular oxidative stress, and ii) has anti-cancer effect in oral cancer cells.