|
type |
Journal Article |
authors |
Kraus, J.; Packman, S.; Fowler, B.; Rosenberg, L. E. |
title |
Purification and properties of cystathionine beta-synthase from human liver. Evidence for identical subunits |
journal |
J Biol Chem |
Activity |
4.2.1.22 |
ui |
78242360 |
year |
(1978) |
volume |
253 |
number |
18 |
pages |
6523-8. |
| |
keywords |
Adult |
abstract |
Cystathionine beta-synthase has been purified from human liver more than 3000-fold by a series of steps including high speed centrifugation, ammonium sulfate fractionation, chromatography on hydroxylapatite and DEAE-cellulose, gel filtration, preparative polyacrylamide gel electrophoresis, and glycerol density gradient centrifugation. The enzyme obtained is homogeneous as judged by polyacrylamide gel electrophoresis in four different systems: native, isoelectric focusing, in sodium dodecyl sulfate, and in 8 M urea. The native enzyme has an estimated molecular weight of 94,000 and is composed of two apparently identical subunits of 48,000. The pure enzyme has a specific activity of 160 units/mg of protein and contains tightly bound cofactor, pyridoxal 5' -phosphate. It is possesses serine sulfhydrase as well as cystathionine synthase activity. It has a broad pH optimum from 8.4 to 9.0, apparent Km values for L-serine of 1.15 mM and for L-homocysteine of 0.59 mM, and a pI of 5.2 The enzyme is stable over a pH range from 6.5 to 8.0 in phosphate buffers and can be stored in 40% glycerol at -15 degrees C for at least 1 month. |
last changed |
2002/11/12 16:17 |
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