Cytotechnology, 6, 115-120, 1991.[PubMed 1367405]

Immunoglobulin production stimulating factor-II (IPSF-II) is the glyceraldehyde-3-phosphate dehydrogenase like protein.

Takuya Sugahara, Sanetaka Shirahata, Kazuhiko Akiyoshi, Toshiaki Isobe, Tsuneo Okuyama, and Hiroki Murakami


Amino acid sequence of the 36 KD protein which is the active subunit of immunoglobulin production stimulating factor-II (IPSF-II) derived from burkitt's lymphoma Namalwa cells was analyzed for the 20 amino acids from N-terminus. N-terminal amino acid sequence of this protein highly coincided with glyceraldehyde-3-phosphate dehydrogenase (GPD; EC derived from various origins. Especially, it was completely coincided with that of human liver GPD. Several GPDs derived from human erythrocyte, rabbit muscle and Bacillus stearothermophilus also stimulated IgM production of hybridomas as well as IPSF-II. Reversely, IPSF-II had GPD enzymic activity as strong as rabbit muscle and B.stearothermophilus and more stronger than human erythrocyte GPD. These results suggested that 36 KD subunit of IPSF-II was the GPD or GPD like protein. Level of the mRNA for IgM was not enhanced by IPSF-II in hybridoma cells, though the IgM productivity of the cell was remarkably stimulated by the protein, indicating that IPSF-II does not stimulate immunoglobulin production the way of enhancement of transcription.