Nemifitide: Molecular Structure

Molecular Structure#

Nemifitide (INN-00835) is a synthetic pentapeptide analog of melanocyte-inhibiting factor (MIF-1). Its sequence incorporates two non-standard amino acids: 4-fluorophenylalanine at position 1 and trans-4-hydroxyproline at position 2. The C-terminal tryptophan is amidated.

Amino Acid Sequence#

Key Structural Modifications#

4-Fluorophenylalanine (Position 1)#

The fluorine substitution at the para position of phenylalanine enhances lipophilicity and metabolic stability while improving receptor binding characteristics. This modification is a common strategy in peptide medicinal chemistry.

trans-4-Hydroxyproline (Position 2)#

Hydroxyproline constrains the peptide backbone conformation, potentially improving receptor selectivity and reducing conformational flexibility compared to proline in the parent MIF-1.

C-Terminal Tryptophan Amide#

The tryptophanamide C-terminus provides an indole moiety important for serotonergic receptor interaction and protects against carboxypeptidase degradation.

Pharmacokinetic Properties#

Phase 1 pharmacokinetic studies in healthy volunteers demonstrated rapid absorption (Cmax at 10 minutes) and elimination (half-life 15-30 minutes) after subcutaneous injection. Despite the short half-life, pharmacodynamic effects persist for days, suggesting receptor-level adaptations outlast plasma drug exposure.

Stability Characteristics#

Nemifitide is typically supplied as the ditrifluoroacetate (diTFA) salt form for stability. Lyophilized material should be stored at -20 degrees C. The compound is inactive orally, necessitating parenteral administration.

Molecular Context#

Nemifitide belongs to the Neuropeptide category of research peptides. The molecular properties of Nemifitide determine its pharmacological behavior, including receptor binding, distribution, metabolism, and elimination. Understanding these properties is fundamental to interpreting clinical data and designing research protocols.

Structural Overview#

Nemifitide is characterized as: Nemifitide is a synthetic pentapeptide with the sequence 4-fluorophenylalanyl-trans-4-hydroxyproline-arginyl-glycyl-tryptophanamide. The 4-fluorophenylalanine and trans-4-hydroxyproline are non-natural amino acid modifications that improve receptor binding affinity and metabolic stability compared to native MIF-1..

Amino Acid Sequence Details#

The amino acid sequence of Nemifitide is: 4-F-Phe-trans-4-OH-Pro-Arg-Gly-Trp-NH2. This sequence determines the peptide's three-dimensional structure, receptor binding properties, and biological activity.

Pharmacokinetic Profile#

Half-Life: 15-30 minutes

The half-life of a peptide influences dosing frequency, duration of effect, and the clinical utility of the compound. Researchers should consider the half-life when designing experimental protocols.

Related Reading#

• Nemifitide overview and research guide
• Peptides similar to Nemifitide
• Nemifitide research evidence