tailieunhanh - Báo cáo y học: " Research How is the balance between protein synthesis and degradation achieved"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Research How is the balance between protein synthesis and degradation achieved? | Rothman Theoretical Biology and Medical Modelling 2010 7 25 http content 7 1 25 THEORETICAL BIOLOGY AND MEDICAL MODELLING RESEARCH Open Access How is the balance between protein synthesis and degradation achieved Stephen Rothman Correspondence 1 University of California San Francisco San Francisco CA 94143 USA Full list of author information is available at the end of the article Abstract Unlike most substances that cells manufacture proteins are not produced and broken down by a common series of chemical reactions but by completely different independent and disconnected mechanisms that possess no intrinsic means of making the rates of the two processes equal and attaining steady state concentrations. Balance between them is achieved extrinsically and is often imagined today to be the result of the actions of chemical feedback agents. But however instantiated chemical feedback or any similar mechanism can only rectify induced imbalances in a system previously balanced by other means. Those other means necessarily involve reversible mass action or equilibriumbased interactions between native and altered forms of protein molecules somewhere in time and space between their synthesis and degradation. Introduction While developing successful all-encompassing or general models to account for life s properties is the hope of much scientific research in biology life s varied and complex nature at times seems to preclude easy generalization. Protein metabolism the events that make and degrade proteins as well as the mechanisms that regulate the rates of these processes is a case in point. Not only is each protein for instance the many thousands of different kinds manufactured by eukaryotic cells structurally and functionally unique so is the path variety variability and duration of their life history. After synthesis some undergo major physical and chemical changes for reasons as varied as the changes themselves while others seem to