Functional lysosomal hydrolase size as determined by radiation inactivation analysis.
Electron inactivation analysis with 16 MeV electrons was used to determine the functional target size of a number of commonly studied lysosomal hydrolases. Observed values ranged from a low of 62 000 +/- 4000 Da for beta-galactosidase to a high of 200 000 +/- 17 500 Da (mouse beta-glucuronidase). One group of lysosomal hydrolases (N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, alpha-galactosidase, beta-mannosidase, beta-glucosidase, arylsulphatase A and sphingomyelinase) had target sizes in the range 100 000-120 000 Da, whereas alpha-glucosidase and alpha-fucosidase exist as complex multimers in the 150 000-160 000 Da range. Analysis of freeze-dried cell material showed little evidence of species (mouse versus human) variation in the functional size of most lysosomal hydrolases with the exception of beta-glucuronidase. Our findings suggest the potential usefulness of lysosomal hydrolases as endogenous marker enzymes in studies where the target size of proteins of unknown molecular mass is to be determined.
Dawson
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Ellory
J C
JC
D000818:Animals; D002478:Cells, Cultured; D004583:Electrons; D006596:Hexosaminidases / Q000528:radiation effects; D006801:Humans; D006867:Hydrolases / Q000528:radiation effects; D008247:Lysosomes / Q000201:enzymology*; D008722:Methods; D051379:Mice; D008970:Molecular Weight; D051381:Rats; D013045:Species Specificity; D001619:beta-N-Acetylhexosaminidases
D006867:Hydrolases; D006596:Hexosaminidases; D001619:beta-N-Acetylhexosaminidases