Interaction of L-asparate β-decarboxylase with β-chloro-L-alanine. β-Elimination reaction and active-site labeling

Cysteine Sulfinate Desulfinase, a NIFS-like Protein ofEscherichia coli with Selenocysteine Lyase and Cysteine Desulfurase Activities

“…The molecular weight of the homogeneous preparation of the gene product estimated by SDS-PAGE (27) (about 43,000) agreed with the value calculated from the deduced amino acid sequence (43,238). The N-terminal amino acid sequence of the purified protein agreed with that deduced from the nucleotide sequence (Fig.…”

“…Alternatively, if no cysteine dioxygenase occurs in E. coli, the cysteine desulfination may be a side function of the enzyme with no metabolic relevance. Aspartate ␤-decarboxylase and aspartate aminotransferase also use cysteine sulfinate as a good substrate and desulfinate it (29,43,47). Whatever the physiological function of cysteine sulfinate desulfinase is, this is the first enzyme in Group II whose catalytic function has been clarified (Fig.…”

Inhibition of Bacterial Growth by β-Chloro-D-Alanine

“…In our studies, comparison of the two enantiomers of chloroalanine, however, show that whereas the -isomer is as effective in the inhibition of bacterial growth as the D-isomer, the prevention of inhibition by D-alanine is much less effective for 0-chloro-i-alanine than for ,3-chloro-D-alanine. Based on these studies and on the reported inactivation of decarboxylases and transaminases for iamino acids by f3-chloro-ialanine (8,20), we expect that 0-chloro-L-alanine would be less specific in its spectrum of reactivity and would probably lead to loss of viability of bacterial and mammalian cells by blocking the production of essential -amino acids.…”

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i3-Chloroamino acids have been shown recently to bind efficiently to transaminases and decarboxylases and to undergo #3-elimination reactions in situ (7,8). In some cases the enzyme catalyzing the (3-elimination reaction is irreversibly inactivated presumably by reaction of the enzyme-bound aminoacrylic acid with some functional group of the protein (8).

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“…In some cases the enzyme catalyzing the (3-elimination reaction is irreversibly inactivated presumably by reaction of the enzyme-bound aminoacrylic acid with some functional group of the protein (8). Accordingly, it has occurred to us that (3-chloro-D-alanine might inhibit irreversibly the pyridoxal phosphate enzymes responsible for the formation of D-alanine in bacterial cells and thereby preclude the synthesis of a cell-wall constituent necessary for bacterial growth.…”