MetaCyc Polypeptide: nitrile hydratase β subunit

Gene: nhhB Accession Number: G-11946 (MetaCyc)

Species: Rhodococcus rhodochrous

Component of: nitrile hydratase (summary available)

Gene Citations: [Kobayashi91]

Molecular Weight of Polypeptide: 26.322 kD (from nucleotide sequence), 29.0 kD (experimental) [Nagasawa91 ]

Unification Links: Protein Model Portal:P21220, UniProt:P21220

Relationship Links: Entrez-Nucleotide:PART-OF:X64359, InterPro:IN-FAMILY:IPR003168, InterPro:IN-FAMILY:IPR008990, InterPro:IN-FAMILY:IPR024690, Pfam:IN-FAMILY:PF02211

Gene-Reaction Schematic

Gene-Reaction Schematic

Revised 02-Apr-2010 by Caspi R, SRI International

Subunit of: nitrile hydratase

Species: Rhodococcus rhodochrous

Subunit composition of nitrile hydratase = [NhhA]2[NhhB]2
         nitrile hydratase α subunit = NhhA
         nitrile hydratase β subunit = NhhB

This enzyme from Rhodococcus rhodochrous contains 2 Co2+ atoms per mol of enzyme. It is similar to the Co-dependent enzyme from Rhodococcus YH3-3, and differs from the Fe-dependent enzymes of Pseudomonas chlororaphis B23 and Rhodococcus sp. R312 [Kato99]. The enzyme is induced by amides, nitriles, and various aldoximes, and is inhibited by heavy metal ions and carbonyl reagents.

The enzyme from Rhodococcus rhodochrous has been purified andf characterized, and the genes encoding it identified and sequenced [Nagasawa91, Kobayashi91, Komeda96]. The enzyme had a wide substrate specificity, and accepts aliphatic saturated, unsaturated nitriles and aromatic nitriles [Nagasawa91].

Revised 02-Apr-2010 by Caspi R, SRI International

Enzymatic reaction of: 3-cyanopyridine hydratase (nitrile hydratase)

Inferred from experiment

3-cyanopyridine + H2O → nicotinamide

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: aldoxime degradation

Cofactors or Prosthetic Groups: Co2+ [Nagasawa91]

T(opt): 35 °C [Nagasawa91]

pH(opt): 6.5-6.8 [Nagasawa91]


Kato99: Kato Y, Tsuda T, Asano Y (1999). "Nitrile hydratase involved in aldoxime metabolism from Rhodococcus sp. strain YH3-3 purification and characterization." Eur J Biochem 1999;263(3);662-70. PMID: 10469129

Kobayashi91: Kobayashi M, Nishiyama M, Nagasawa T, Horinouchi S, Beppu T, Yamada H (1991). "Cloning, nucleotide sequence and expression in Escherichia coli of two cobalt-containing nitrile hydratase genes from Rhodococcus rhodochrous J1." Biochim Biophys Acta 1129(1);23-33. PMID: 1840499

Komeda96: Komeda H, Kobayashi M, Shimizu S (1996). "Characterization of the gene cluster of high-molecular-mass nitrile hydratase (H-NHase) induced by its reaction product in Rhodococcus rhodochrous J1." Proc Natl Acad Sci U S A 93(9);4267-72. PMID: 8633053

Nagasawa91: Nagasawa T, Takeuchi K, Yamada H (1991). "Characterization of a new cobalt-containing nitrile hydratase purified from urea-induced cells of Rhodococcus rhodochrous J1." Eur J Biochem 196(3);581-9. PMID: 2013281

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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