title: Preparation of immunomodulatory hydrolysates from Alaska pollock frame.
abstract: BACKGROUND
  Immunomodulatory peptides can enhance body immunity. There have been few systematic investigations on preparing immunomodulatory peptides from Alaska pollock frame. The aim of this study was to obtain such peptides from Alaska pollock frame and determine their properties.
  
  
  RESULTS
  Trypsin protein hydrolysate (TPH) significantly enhanced the proliferation of spleen lymphocytes, T cells and peritoneal macrophages (P < 0.05). Compared with TPH with molecular weight (MW) > 2 kDa, TPH with MW < 2 kDa showed higher lymphocyte proliferation activity at 10, 50 and 500 µg ml(-1). The optimised hydrolysis conditions were a temperature of 50 °C, an enzyme dose of 24 U mg(-1) and a time of 290 min. The proliferation rate and degree of hydrolysis were 28.45 ± 1.79% and 16.87 ± 0.15% respectively. The main amino acids in TPH were proline, aspartate, glutamic acid and leucine. TPH had high solubility and low viscosity. TPH showed high stability under both acid and alkaline conditions or when digested by trypsin and/or pepsin.
  
  
  CONCLUSIONS
  TPH showed high immunomodulatory activity, with molecular weight and amino acid composition being the important factors affecting this activity. TPH had high solubility, low viscosity and high stability. As a good immunomodulator, TPH may therefore have wide application.
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, Shandong China.
authors.forename: Hu
authors.initials: H
authors.lastname: Hou
authors.forename: Yan
authors.initials: Y
authors.lastname: Fan
authors.forename: Bafang
authors.initials: B
authors.lastname: Li
authors.forename: Changhu
authors.initials: C
authors.lastname: Xue
authors.forename: Guangli
authors.initials: G
authors.lastname: Yu
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D004355:Drug Stability; D005260:Female; D029941:Fish Proteins / Q000378:metabolism; D048388:Gadiformes; D006868:Hydrolysis; D007155:Immunologic Factors / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects; D008262:Macrophage Activation / Q000187:drug effects; D051379:Mice; D008970:Molecular Weight; D011492:Protein Hydrolysates / Q000737:chemistry* / Q000494:pharmacology*; D014357:Trypsin / Q000378:metabolism
chemical_list: D000596:Amino Acids; D029941:Fish Proteins; D007155:Immunologic Factors; D011492:Protein Hydrolysates; D014357:Trypsin