title: Catalytic activities of [GADV]-peptides. Formation and establishment of [GADV]-protein world for the emergence of life.
abstract: We have previously postulated a novel hypothesis for the origin of life, assuming that life on the earth originated from "[GADV]-protein world", not from the "RNA world" (see Ikehara's review, 2002). The [GADV]-protein world is constituted from peptides and proteins with random sequences of four amino acids (glycine [G], alanine [A], aspartic acid [D] and valine [V]), which accumulated by pseudo-replication of the [GADV]-proteins. To obtain evidence for the hypothesis, we produced [GADV]-peptides by repeated heat-drying of the amino acids for 30 cycles ([GADV]-P(30)) and examined whether the peptides have some catalytic activities or not. From the results, it was found that the [GADV]-P(30) can hydrolyze several kinds of chemical bonds in molecules, such as umbelliferyl-beta-D-galactoside, glycine-p-nitroanilide and bovine serum albumin. This suggests that [GADV]-P(30) could play an important role in the accumulation of [GADV]-proteins through pseudo-replication, leading to the emergence of life. We further show that [GADV]-octapaptides with random sequences, but containing no cyclic compounds as diketepiperazines, have catalytic activity, hydrolyzing peptide bonds in a natural protein, bovine serum albumin. The catalytic activity of the octapeptides was much higher than the [GADV]-P(30) produced through repeated heat-drying treatments. These results also support the [GADV]-protein-world hypothesis of the origin of life (see Ikehara's review, 2002). Possible steps for the emergence of life on the primitive earth are presented.
authors.affiliation: Department of Chemistry, Faculty of Science, Nara Women's University, Kita-uoya-nishi-machi, Nara 630-8506, Japan.
authors.forename: Takae
authors.initials: T
authors.lastname: Oba
authors.forename: Jun
authors.initials: J
authors.lastname: Fukushima
authors.forename: Masako
authors.initials: M
authors.lastname: Maruyama
authors.forename: Ryoko
authors.initials: R
authors.lastname: Iwamoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Ikehara
mesh_terms: D000409:Alanine / Q000737:chemistry*; D000813:Anilides / Q000737:chemistry; D001224:Aspartic Acid / Q000737:chemistry*; D002384:Catalysis; D002850:Chromatography, Gel; D019418:Evolution, Chemical; D005998:Glycine / Q000737:chemistry*; D000069497:Origin of Life; D010455:Peptides / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014468:Umbelliferones / Q000737:chemistry; D014633:Valine / Q000737:chemistry*
chemical_list: D000813:Anilides; D010455:Peptides; D014468:Umbelliferones; D001224:Aspartic Acid; D014633:Valine; D000409:Alanine; D005998:Glycine