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PubMed · 1055433

Beta-cyanoalanine synthase: purification and characterization.

T N Akopyan·A E Braunstein·E V Goryachenkova
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Abstract

Beta-cyano-L-alanine synthase [L-cysteine hydrogen-sulfide-lyase (adding HCN), EC 4.4.1.9] was purified about 4000-fold from blue lupine seedlings. The enzyme was homoegeneous on gel electrophoresis and free of contamination by other pyridoxal-P-dependent lyases. The enzyme has a molecular weight of 52,000 and contains 1 mole of pyridoxal-P per mole of protein; its isoelectric point is situated at pH 4.7. Its absorption spectrum has two maxima, at 280 and 410 nm. L-Cysteine is the natural primary (amino acid) substrate; beta-chloro- and beta-thiocyano can serve (with considerably lower affinity) instead of cyanide as cosubstrates for cyanoalanine synthase. The synthase is refractory to DL-cycloserine and D-penicillamine, potent inhibitors of many pyridoxal-P-dependent enzymes. Cyanoalanine synthase catalyzes slow isotopic alpha-H exchange in cysteine and in end-product amino acids; the rates of alpha-H exchange in nonreacted (excess) cysteine are markedly increased in the presence of an adequate cosubstrate; no exchange is observed of H atoms in beta-position.

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Amino AcidsAminooxyacetic AcidCarbon-Sulfur LyasesChromatography, GelChromatography, Ion ExchangeCyanidesCycloserineCysteineElectrophoresis, Polyacrylamide GelIsoelectric FocusingKineticsLyasesMolecular WeightPenicillaminePlantsPropionatesPyridoxal PhosphateSpectrophotometrySpectrophotometry, UltravioletTime FactorsJournal Article

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BibTeXRIS

T N Akopyan, A E Braunstein, E V Goryachenkova. 1975. Beta-cyanoalanine synthase: purification and characterization.. https://doi.org/10.1073/pnas.72.4.1617

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