Lysosomes

[Bonkerskitten]

Lysosomes

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Post by Bonkerskitten » Fri Jul 20, 2007 12:14 pm

Can anyone tell me why protein-digesting enzymes in lysosomes are enclosed within membranes??

Thanks.

[blcr11]

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Post by blcr11 » Fri Jul 20, 2007 4:04 pm

I’m not a proper cell biologist, but my understanding is that the lysosomal membrane is designed to separate the lytic enzymes from the rest of the cell. It’s sorted in the trans-golgi and the inactive lysosome buds off into the cytoplasm. The membrane is able to fuse with other vesicles or vacuoles in much the same way that the external membranes can fuse with or extrude vesicles. Putting all the lytic enzymes together in one type of vacuole (or whatever the correct name is) is a convenient way to keep the lytic enzymes together and relatively inactive. These enyzmes typically have low pH optimums, so when the lysosome is needed, the membrane can pump protons to acidify the interior thus activating the enzymes—in a bunch. And that’s what I know about the lysosome.

[Darby]

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Post by Darby » Sun Jul 22, 2007 3:34 pm

Also, when they are let out of the membranes, they digest the contents of the cell, a common way to perform apoptosis, cell "suicide."