Alpha- 1-antitrypsin (AAT), also referred to as SERPIN A1, is the most abundant serine protease inhibitor (PI; serpin) in human plasma. It is a glycoprotein with broad inhibitory capacity against a variety of serine proteases and its main physiological target is neutrophil elastase. The three-dimensional structure of AAT and other serpins has provided major insights into the mechanism of inhibition of cognate proteases. AAT is a globular protein with an exposed reactive center loop (RCL). The protease docks on to the RCL, and cleavage of a methionine-serine bond at positions 358-359 in the loop results in a major confor-mational change. The loop inserts into a space in the A-sheet as a strand, and the protease then moves to the opposite pole of the molecule. During this translocation process, the catalytic site of the serine protease is distorted so that it is rendered inactive (Fig. 1). The PI complex is then rapidly removed from the circulation. This is a very efficient mechanism for controlling serine protease activity.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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