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CATH Superfamily 3.40.50.1100

The name of this superfamily has been modified since the most recent official CATH+ release (v4_3_0). At the point of the last release, this superfamily was: waiting to be named.

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.
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FunFam 6: Cysteine synthase

There are 8 EC terms in this cluster

Please note: EC annotations are assigned to the full protein sequence rather than individual protein domains. Since a given protein can contain multiple domains, it is possible that some of the annotations below come from additional domains that occur in the same protein, but have been classified elsewhere in CATH.

Note: The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.

EC Term Annotations Evidence
Cysteine synthase. [EC: 2.5.1.47]
O-acetyl-L-serine + hydrogen sulfide = L-cysteine + acetate.
  • Some alkyl thiols, cyanide, pyrazole and some other heterocyclic compounds can act as acceptors.
  • Not identical with EC 2.5.1.51, EC 2.5.1.52 and EC 2.5.1.53.
  • Formerly EC 4.2.99.8.
 701 A0A045JQB5 A0A045JQB5 A0A045JQB5 A0A045JQB5 A0A045JQB5 A0A045JQB5 A0A045JQB5 A0A045JQB5 A0A045JQB5 A0A045JQB5
(691 more...)
Cystathionine beta-synthase (O-acetyl-L-serine). [EC: 2.5.1.134]
O-acetyl-L-serine + L-homocysteine = L-cystathionine + acetate.
  • The enzyme, purified from the bacterium Bacillus subtilis, also has a low activity with L-serine (cf. EC 4.2.1.22).
 25 A0A164WZQ2 A0A164WZQ2 A0A164WZQ2 A0A164WZQ2 A0A164WZQ2 A0A410R3E5 A0A410R3E5 A0A410R3E5 A0A410R3E5 A0A410R3E5
(15 more...)
L-3-cyanoalanine synthase. [EC: 4.4.1.9]
L-cysteine + hydrogen cyanide = L-3-cyanoalanine + hydrogen sulfide.
    		 11 A0A178VGN1 A0A178VGN1 O45679 Q1KLZ1 Q1KLZ2 Q43153 Q76MX2 Q9S6Z7 Q9S757 Q9S757
    (1 more...)
    S-sulfo-L-cysteine synthase (O-acetyl-L-serine-dependent). [EC: 2.5.1.144]
    O-acetyl-L-serine + thiosulfate = S-sulfo-L-cysteine + acetate.
    • In plants, the activity is catalyzed by a chloroplastic enzyme that plays an important role in chloroplast function and is essential for light-dependent redox regulation within the chloroplast.
    • The bacterial enzyme also catalyzes the activity of EC 2.5.1.47.
    • Cf. EC 2.8.5.1.
    		 4 A0A178VH77 A0A178VH77 O22682 O22682
    Beta-pyrazolylalanine synthase. [EC: 2.5.1.51]
    O-acetyl-L-serine + pyrazole = 3-(pyrazol-1-yl)-L-alanine + acetate.
    • Highly specific for acetylserine and pyrazole.
    • Not identical with EC 2.5.1.52.
    • Formerly EC 4.2.99.14 and EC 4.2.99.17.
    		 1 Q43317
    L-mimosine synthase. [EC: 2.5.1.52]
    O-acetyl-L-serine + 3,4-dihydroxypyridine = 3-(3,4-dihydroxypyridin-1- yl)-L-alanine + acetate.
    • Brings about the biosynthesis of L-mimosine in Leucaena sp. and Mimosa.
    • Not identical with EC 2.5.1.51.
    • Formerly EC 4.2.99.15.
    		 1 Q43317
    Pyrazolylalanine synthase. [EC: 4.2.1.50]
    L-serine + pyrazole = 3-(pyrazol-1-yl)-L-alanine + H(2)O.
      		 1 Q43317
      Cystathionine gamma-lyase. [EC: 4.4.1.1]
      L-cystathionine + H(2)O = L-cysteine + NH(3) + 2-oxobutanoate.
      • The enzyme cleaves a carbon-sulfur bond, releasing L-cysteine and an unstable enamine product that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form 2-oxobutanoate and ammonia.
      • The latter reaction, which can occur spontaneously, can also be catalyzed by EC 3.5.99.10.
      • Also catalyzes the conversion of L-homoserine to 2-oxobutanoate and ammonia, of L-cystine to thiocysteine, pyruvate and ammonia, and of L-cysteine to pyruvate, hydrogen sulfide and ammonia.
      • Formerly EC 4.2.1.15.
      		 1 F4K5T2
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