Isolation and primary structure of human PHI (peptide HI)

Area of Science:

• Biochemistry
• Peptide Chemistry
• Human Physiology

Background:

• Peptide HI (PHI) is a biologically active peptide found in various mammalian tissues.
• Understanding species-specific peptide structures is crucial for comparative physiology and pharmacology.

Purpose of the Study:

• To isolate and characterize the human form of peptide HI (PHI).
• To determine the complete amino acid sequence of human PHI.
• To identify structural differences between human and porcine PHI.

Main Methods:

• Purification of human PHI from human colonic extracts.
• Chemical methods employed for the detection of C-terminal amidation.
• Amino acid sequencing to elucidate the peptide's structure.

Main Results:

• Human PHI was successfully isolated and purified.
• The complete 27-amino acid sequence of human PHI was determined: His-Ala-Asp-Gly-Val-Phe-Thr-Ser-Asp-Phe-Ser-Lys-Leu-Leu-Gly-Gln-Leu-Ser-Ala-Lys-Lys-Tyr-Leu-Glu-Ser-Leu-Met-NH2.
• Key structural differences were identified at position 12 (Arg in porcine vs. Lys in human) and position 27 (Ile in porcine vs. Met in human).

Conclusions:

• The complete structure of human peptide HI has been elucidated.
• Human PHI exhibits distinct structural variations compared to its porcine counterpart, particularly in amino acid residues at positions 12 and 27.
• This characterization provides a basis for further research into the physiological roles and potential therapeutic applications of human PHI.