From owner-metabolic-reg@net.bio.net Sun Mar 26 23:00:00 1995 Path: biosci!bloom-beacon.mit.edu!gatech!swrinde!howland.reston.ans.net!news.sprintlink.net!uunet!fdn.fr!jussieu.fr!univ-lyon1.fr!swidir.switch.ch!scsing.switch.ch!news.rccn.net!master.di.fc.ul.pt!skull.cc.fc.ul.pt!elitro From: Nuno Martins Newsgroups: bionet.metabolic-reg Subject: help on lysossomes Date: Mon, 27 Mar 1995 13:30:33 +0100 Organization: Faculdade de Ciencias da Universidade de Lisboa Lines: 32 Message-ID: NNTP-Posting-Host: skull.cc.fc.ul.pt Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII I'm a portuguese high school biology teacher. Some time ago, a student of mine put me a question to wich I'm having some trouble finding a suitable answer. 1- Since hydrolases packed in lysossomes are isolated from cytosdol by a single membrane,which contains lipids,Glycids and proteins,why do these hydrolases (including lypases,glycolases and proteases) do not destroy these membrane? All the books I searched just ommited this particularity,or said that nothing is known about this. In "Molecular Biology of the Cell" I found there was a relationship between the high glycosilation of lysossomic membranes, and their indestructibility but this is just too vague to be able to clarify me (or anybody else for that matter). 2- Since the lysossomic hydrolases only act at low pH values, how do they perform autolysis of the cell(the cytosol pH is about 7.2,I believe)? Once again i couldn't even find the topic autolysis in my books,so, information was, again, inexistant. Thank you in advance,any answers will be welcome. My best regards, Nuno de Oliveira Martins Performing probation at Sciences College - University of Lisbon Lisbon - Portugal .