| 摘要 |
PCT No. PCT/GB88/00758 Sec. 371 Date Feb. 22, 1990 Sec. 102(e) Date Feb. 22, 1990 PCT Filed Sep. 16, 1988 PCT Pub. No. WO89/02917 PCT Pub. Date Apr. 6, 1989.Increased yields of enzymes, particularly tissue plasminogen activator (tPA), are produced from cells, particularly CNCM I-222 cells, by a process using less concentrated lectin, particularly concanavalin A, in culture medium added to replace initial growth medium than has been used hitherto. After first harvesting of enzyme in supernatants, the culture can be reactivated by the addition of fresh culture medium containing an even lower lectin concentration, and a further harvest of enzyme obtained. The two harvests of enzyme together can give a greater overall yield than a single harvest after a single induction step employing the conventionally used higher lectin concentrations. Enzyme yield can be further increased by repeating the last incubation step once or twice to obtain one or two further harvests.
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