Heat Resistant Characteristics of Major Royal Jelly Protein 1 (MRJP1) Oligomer

PLoS One. 2015 May 28;10(5):e0119169. doi: 10.1371/journal.pone.0119169. eCollection 2015.


Soluble royal jelly protein is a candidate factor responsible for mammiferous cell proliferation. Major royal jelly protein 1 (MRJP1), which consists of oligomeric and monomeric forms, is an abundant proliferative protein in royal jelly. We previously reported that MRJP1 oligomer has biochemical heat resistance. Therefore, in the present study, we investigated the effects of several heat treatments (56, 65 and 96°C) on the proliferative activity of MRJP1 oligomer. Heat resistance studies showed that the oligomer molecular forms were slightly maintained until 56℃, but the molecular forms were converted to macromolecular heat-aggregated MRJP1 oligomer at 65℃ and 96℃. But, the growth activity of MRJP1 oligomer treated with 96°C was slightly attenuated when compared to unheated MRJP1 oligomer. On the other hand, the cell proliferation activity was preserved until 96℃ by the cell culture analysis of Jurkat cells. In contrast, those of IEC-6 cells were not preserved even at 56°C. The present observations suggest that the bioactive heat-resistance properties were different by the origin of the cells. The cell proliferation analysis showed that MRJP1 oligomer, but not MRJP2 and MRJP3, significantly increased cell numbers, suggesting that MRJP1 oligomer is the predominant proliferation factor for mammiferous cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cell Proliferation / drug effects
  • Fatty Acids / metabolism*
  • Glycoproteins / chemistry
  • Glycoproteins / isolation & purification
  • Glycoproteins / pharmacology*
  • Hot Temperature
  • Humans
  • Insect Proteins / chemistry
  • Insect Proteins / isolation & purification
  • Insect Proteins / pharmacology*
  • Jurkat Cells
  • Rats


  • Fatty Acids
  • Glycoproteins
  • Insect Proteins
  • royal jelly

Grant support

This study was supported by a Sapporo Regional Innovation Strategy Promotion Program Grant from the Knowledge Cluster Initiative of the Ministry of Education, Sports, Science and Technology (MEXT) and by Japan Royal Jelly Co., Ltd. Other research funds were provided from the internal funds of Hokkaido University, Sapporo, Japan. Japan Royal Jelly Co., Ltd., did not have any role in the study design, data collection and analysis, decision to publish or preparation of the manuscript.