2001 Fiscal Year Final Research Report Summary
Receptors and biosynthesis of peptide plant cell growth factor, phytosulfokine
| Project/Area Number |
12460148
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied molecular and cellular biology
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| Research Institution | Nagoya University |
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Principal Investigator |
SAKAGAMI Youji Graduate School of Bioagricultural Sciencesy,Nagova University Professor, 大学院・生命農学研究科, 教授 (80107408)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUBAYASHI Yoshikatsu Graduate School of Bioagricultural Sciencesy,Nagova University Assistant Professor, 大学院・生命農学研究科, 助手 (00313974)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Phytcsulfokine / Receptor / Photoaffinity / Sulfotranseferase |
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| Research Abstract |
Peptide plant growth factor, phytosulfokine (PSK) discovered by us, has only five amino acid residues and seems to reveal biological activities via receptorfe) on membrane similar manner of mammal growth factors. We proved that there were the PSK specific binding sites on the rice membrane. On this study, we found that these binding sites were having 120 and 160 kD molecular weight by means of photoafflnity label of PSK derivative. These molecules decrease the molecular weight 10 kD by the treatments of glycosidase. These proteins should be the PSK receptor and the purification of these receptors are now under going.
Two tyrosine residues in PSK molecule are both sulfated and these sutfation is necessary to impress the biological activities of PSK. The sulfated tyrosine residues in peptide or protein are abundant modification in animals, however in plant, PSK is the first example and only eaxample until now. Therefore, we began to investigate the plant tyrosil protein sulfotransferase (TPST). Referring animal TPSK researches, we extracted and examined the enzyme activities from several kinds of plant cells which produce PSK. Asparagus cultured cell showed most active source of the TPSK. The properties of this TPSK were similar to those of animal TPSK reported except the optimum pH. We used the partial sequence of PSK precursor or its derivatives as the enzyme substrate and the aspartic acid just before the sequence of PSK showed the most important amino acid for the sulfation that was the same to the animal case. We also purified this enzyme approximately 100 folds. We found that the molecular weight of this plant TPSK was 61-62 kD.
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