上浒充通大淫 SHANGHAI JIAO TONG UNIVERSITY Major Modes of Regulation Two major levels of regulation in the cell: One controls the activity of preexisting enzymes Posttranslational regulation Very rapid process (seconds) 。 One controls the amount of an enzyme Regulate level of transcription Regulate translation Slower process (minutes) CHEN FENG,School of Life Sciences and Biotech.CHEN FENG，School of Life Sciences and Biotech. Major Modes of Regulation Two major levels of regulation in the cell: • One controls the activity of preexisting enzymes • Posttranslational regulation • Very rapid process (seconds) • One controls the amount of an enzyme • Regulate level of transcription • Regulate translation • Slower process (minutes)