Amino acids phospho

Protein phosphatases are several classes of enzymes that catalyze the hydrolysis of phospho-amino acids within a peptide or protein, thus resulting in dephosphorylation. 

Protein phosphatases are classified according to their activity toward phospho-amino acids they act on (Fig. 1). Nomenclature is independent of regulation simply because stimuli were unknown. Protein phosphatases hydrolyzing O-phospho-monoesters are currently subdivided into two major classes (i) phosphatases acting on phosphoserine (pSer) and phosphothreonine (pThr), and (ii) the second class... 

All vertebrates can form certain amino acids from amphibolic intermediates or from other dietary amino acids. The intermediates and the amino acids to which they give rise are a-ketoglutarate (Gin, Gin, Pro, Hyp), oxaloacetate (Asp, Asn) and 3-phospho-glycerate (Ser, Gly). 

From Sigma 3-aminoethylcarbazole (AEC) acrylamide/bis-acrylamide (30%) 37.5 1 amino acids alumina bentonite benzamidine bovine fiver tRNA bovine serum albumin (BSA) creatine phosphate (CP) diethyl pyrocarbonate (DEPC) dithiothreitol (DTT) Escherichia coli MRE600 tRNA pyrophosphatase (Ppase) Ca++ salt of folinic acid, (5-formyl THF) IIHPHS K salt of phospho-enol pyruvic acid, (PEP) creatine phospho kinase (CPK) protease inhibitor cocktail for fungal and yeast extracts phenylmethylsulfonyl fluoride (PMSF) spermidine trihydrochloride Tween 20. 

Neuronal phosphoproteins differ considerably in the number and types of amino acid residues phospho-rylated. The complexity of intracellular regulation is underscored by the now numerous and well-established observations of numerous proteins that are phosphory-lated on more than one amino acid residue by more than... 

Hie first protein kinase obtained in a purified form was the Ser/Thr-specific phospho-rylase kinase of muscle, in 1959 (Krebs et al., 1959). With the discovery of the Tyr-specific protein kinases (Erikson et al., 1979), the Ser/Thr-specific protein kinases were joined by another extensive class of protein kinases of regulatory importance, to which a central function in growth and differentiation processes was soon attributed. At present, several hrmdred different protein kinases are known in mammals, most of which are Ser/Thr- or Tyr-specific. In addition, there are some protein kinases that phospho-rylate other amino acids (review Hrmter, 1991). 

The six carbons of the benzene ring of the aromatic amino acids are derived from the four carbons of erythrose 4-phosphate and two of the three carbons of phosphoenolpyruvate (PEP). The initial step in the pathway (Fig. 25-1, step a) is the condensation of erythrose 4-P with PEP and is catalyzed by 3-deoxy-D-arafrmo-heptulosonate-7-phosphate (DAHP) synthase. Closely analogous to an aldol condensation, the mechanism provides a surprise.10 When PEP containing lsO in the oxygen bridge to the phospho group reacts, the lsO is retained in the eliminated phosphate biochemical intuition would suggest that it should stay in the... 

Several nickel(II) complexes have been reported with Schiff bases derived from the condensation of salicylaldehyde and various amino acids. The structures of the complexes were investigated by means of electronic and NMR spectra as well as X-ray crystallography.2336-2341 Recently the X-ray structure of complex (321), prepared by the reaction of pyridoxal-HCl, o-phospho-DL-threonine and N NOsVfiHaO at pH 5, has been reported.2341... 

Fig. 1. Structure of CoA, composed of three parts a nucleotide pan derived from 3 -adenosine-5 -pbosphate, forming a phosphodiester bond with a 4-phospho derivative of pantothenic acid, and a third pan derived horn the amino acid, cysteine. The side chain SH group of the latter is ftee in this compound and is readily acylated, and thus able to act as a carrier for acyl groups in biochemical reactions in which it transfers that group between two substrates...

In contrast to the FDPases isolated from mammalian tissues, which are active with both FDP and SDP, the enzyme in Candida utilis is completely specific for FDP. A second activity, which catalyzes the hydrolysis of SDP to S7P, has been purified from this organism. The specific SDPase differs from the FDPase in lacking the requirement for the divalent metal cation and in showing optimum activity at neutral pH. Recently, the presence of distinct FDP and SDPases in this organism has been confirmed by the separation of these enzymes in phospho-cellulose chromatography and by the isolation of each enzyme in pure form (84). The purified FDPase and SDPase were found to differ in molecular weight and amino acid composition. 

JY Chang. Analysis of phospho-amino acids and amino acid amides at the picomole level using 4 -dimethylaminoazobenzene-4-sulphonyl chloride. J Chromatogr 295 193-200, 1984. 

The hydrolysis reactions of A -phospho amino acids seen as models for protein dephosphorylation have been studied in Tris-HCl buffer (pH7.5)-DMSO. The reactions were first order and the rates were very much faster than those of simple phosphoamidates. A pentacoordinated phosphorus intermediate is proposed on the reaction pathway.265 The rates of ester exchange reactions of alcohols (nucleoside models) with the oxyphosphorane (299) have been studied and the rates of exchange are much faster for diols than for mono-alcohols.266... 

---