O-Sulphate esters of l-serine, l-threonine and l-hydroxyproline

Biosynthesis of L-tyrosine O-sulphate from the Methyl and Ethyl Esters of L-tyrosine.

1. Rat-liver supernatant preparations are capable of achieving the biological sulphation of l-tyrosine methyl ester, the reaction proceeding maximally at a substrate concentration of 30 mm and at pH 7.0. 2. Two sulphated products are formed, one of which has been identified as l-tyrosine O-sulphate. On the basis of indirect evidence the other product can be assumed to be l-tyrosine O-sulphate m...

Isolation and Properties of a Homogeneous Preparation of Cystathionine Synthetase-l-serine and L-threonine Dehydratase.

Selim and Greenberg (1, 2) achieved a considerable degree of purification of L-serine dehydratase (L-serine hydro-lyase (deaminating), EC 4.2.1.13) from rat liver and demonstrated that this protein preparation contained the cystathionine-synthesizing activity of the liver (L-serine hydro-lyase (adding L-homocysteine), EC 4.2.1.21). These workers (2) also observed activity of their enzyme prepar...

The enzymatic exchange of L-serine with O-phospho-L-serine catalyzed by a specific phosphatase.

Materials and Methods-nn-Serine-3-C14 was purchased from the Volk Radiochemical Company. n-Serine-3-V and n-serine3-V were generous gifts of Dr. Manfred Karnovsky. Orthophosphate labeled with Ps2 was obtained from the Atomic Energy Commission. ATP labeled in the two terminal phosphates with Ps2 was prepared by a method similar to that of Lowenstein (3). Pi was determined by a procedure based on...

The fermentation of L-threonine, L-serine, L-cysteine and acrylic acid by a gram-negative coccus.

The reversible inactivation of L-threonine hydratase of sheep liver by L-serine.

The action of partially purified L-threonine dehydratase of sheep liver on L-serine has been studied. This enzyme acts on L-serlne as a substrate but is rapidly inactivated in the process, partially at pH 8.9 and more completely at pH 7.2. However, incubation at pH 8.9, with or without L-threonine, leads to a gradual restoration of up to 90% of the original activity. The addition of pyridoxal p...