Skip to content
Login Register

#lysosomal pH

2 public questions tagged with this topic.

Membrane Transportation

Which pump is responsible for maintaining low pH in lysosomes?

Lysosomes function as degradative centers requiring low internal pH between 4.5 and 5 to activate more than fifty acid hydrolases such as cathepsins, sulfatases and lipases, while protecting cytosol from unwanted proteolysis. Acidic environment established primarily by vacuolar proton ATPase V-ATPase, large 900 kilodalton complex composed of peripheral V1 octamer A3B3CDE3FG3H hydrolyzing ATP at A-B interfaces and integral Vo domain a, c, c'', d, e, forming proton pore. Mechanism rotary: ATP hydrolysis in V1 drives rotation of central stalk D F and c-ring proteolipid assembling ten copies each

Ref: Forgac, Nature Reviews Mol Cell Biol, V-ATPase Structure and Lysosomal Acidification Function.

View Details
Cell Organelles

The acidic pH of lysosomes is maintained by:

Lysosomes maintain a highly acidic lumen essential for optimal activity of about sixty acid hydrolases involved in macromolecular digestion and for solute transport. The steep proton gradient, pH 4.5 to 5.0 inside versus cytosolic pH 7.2, representing over two pH units and hundredfold proton concentration difference, is actively generated by vacuolar-type H+ ATPase, V-ATPase, consuming ATP. This massive multi-subunit rotary pump consists of peripheral V1 domain with A3B3 hexamer that hydrolyzes ATP and integral V0 domain forming proton channel with c-ring rotation. ATP hydrolysis drives rotati

Ref: Alberts et al., Molecular Biology of the Cell, 6th ed., Chapter 13: Lysosomes – V-ATPase and Acidification.

View Details