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Changes in microsomal hemoprotein content and glucose 6‐phosphatase activity during low‐temperature acclimation of Tetrahymena pyriformis
Author(s) -
Fukushima Hirofumi,
Watanabe Takehito,
Sasaki Noboru,
Takeda Tomoo,
Nozawa Yoshinori
Publication year - 1983
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(83)81021-7
Subject(s) - tetrahymena , tetrahymena pyriformis , hemeprotein , microsome , cytochrome , biochemistry , cytochrome b5 , chemistry , heme , cytochrome c , biology , enzyme , mitochondrion
To examine the temperture‐associated alterations in microsomal enzymes in an eukaryote, Tetrahymena cells were transferred from 39.5–15°C. The content of cytochrome b ‐560 ms , a cytochrome similar to but not identical with liver microsomal cytochrome b 5 , was slightly increased within 2 h after temperature shift‐down, then gradually decreased, and reached the cytochrome b ‐560 ms level of the 15°C‐isothermally grown cells within 10 h following the temperature‐shift. Cytochrome P‐450 was not detected in Tetrahymena microsomes. The presence of a co‐binding hemoprotein with a main peak at 420 nm was, however, observed. The amount of this hemoprotein was unchanged for 2 h after cold‐shift. Later, it increased gradually and reached the maximum level at 10 h. Glucose 6‐phosphatase activity increased slightly at 10 h, when cell division had already been regained. We conclude that cytochrome b ‐560 ms , which is linked to the desaturase, may be essential for short‐term adaptation (2 h after shift), while the amount of co‐binding hemoprotein and the activity of glucose 6‐phosphatase would be associated with long‐term adaptation (10 h after temperature shift) in Tetrahymena cells.