ShK-192 Peptide

ShK-192 is a synthetic peptide analog derived from ShK, a toxin originally isolated from the sea anemone Stichodactyla helianthus. Designed to address stability and selectivity issues in earlier versions like ShK-170, ShK-192 was engineered to enhance its therapeutic potential for autoimmune diseases (1) (5). The peptide incorporates three key modifications:

- Replacement of the N-terminal phosphotyrosine with a nonhydrolyzable para-phosphonophenylalanine (Ppa) group to prevent hydrolysis
- Substitution of methionine at position 21 with norleucine (Nle) to eliminate oxidation susceptibility, and
- Conversion of the C-terminal carboxyl group to an amide to resist degradation by carboxypeptidases (1) (5) (2).

These changes significantly improve its pharmacokinetic properties while retaining biological activity.

ShK-192 selectively blocks the Kv1.3 potassium channel, a key regulator of effector memory T (TEM) cells implicated in autoimmune disorders such as multiple sclerosis, rheumatoid arthritis, and type 1 diabetes. By binding to Kv1.3 with an IC50 of 140 pM, it disrupts the channel's function, suppressing TEM cell proliferation and inflammatory responses without affecting related channels like Kv1.1 or Kv1.2, achieving over 100-fold selectivity (1) (3) (5). Structural studies using NMR reveal that ShK-192 maintains the same overall fold as the native ShK toxin, with its N-terminal Ppa group forming a salt bridge with Lys411 in the Kv1.3 channel, a critical interaction for its specificity (3) (2).

Preclinical studies demonstrate that subcutaneous administration of ShK-192 (10–100 μg/kg) sustains therapeutic blood concentrations for up to 72 hours and effectively suppresses delayed-type hypersensitivity and autoimmune disease progression in animal models (1)

Its stability under varying pH and temperature conditions makes it suitable for formulation in slow-release systems, such as biodegradable polymers, further enhancing its clinical applicability 1. Additionally, ShK-192’s design avoids immunogenic non-protein components, addressing limitations seen in earlier analogs like ShK-186 (dalazatide), which faced issues with dephosphorylation and antibody generation (5).

Developed through extensive structure-activity optimization, ShK-192 represents a promising candidate for autoimmune therapy, with patents highlighting its role in immunomodulation and ongoing research exploring its broader therapeutic potential (4). Its success in preclinical models underscores the viability of venom-derived peptides as targeted treatments for complex immune-mediated conditions.

1-2 loops is a good dose for the day.