1MGN

HIS64(E7)-> TYR APOMYOGLOBIN AS A REAGENT FOR MEASURING RATES OF HEMIN DISSOCIATION

1MGN の概要

• エントリーDOI: 10.2210/pdb1mgn/pdb
• 分子名称: METMYOGLOBIN, SULFATE ION, PROTOPORPHYRIN IX CONTAINING FE, ... (4 entities in total)
• 機能のキーワード: oxygen transport
• 由来する生物種: Physeter catodon (sperm whale)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 18102.74

構造登録者

Hargrove, M.S.,Quillin, M.L.,Phillips Jr., G.N. (登録日: 1993-10-29, 公開日: 1994-01-31, 最終更新日: 2024-02-14)

主引用文献

Hargrove, M.S.,Singleton, E.W.,Quillin, M.L.,Ortiz, L.A.,Phillips Jr., G.N.,Olson, J.S.,Mathews, A.J.
His64(E7)-->Tyr apomyoglobin as a reagent for measuring rates of hemin dissociation.
J.Biol.Chem., 269:4207-4214, 1994

PubMed Abstract: To develop an assay for hemin dissociation, His64(E7) was replaced by Tyr in sperm whale myoglobin producing a holoprotein with a distinct green color due to an intense absorption band at 600 nm. Val68(E11) was replaced by Phe in the same protein to increase its stability. When excess Tyr64-Val68 apoglobin is mixed with either metmyoglobin or methemoglobin, the solution turns from brown to green, and the absorbance changes can be used to measure complete time courses for hemin dissociation from either holoprotein. This assay has been used to measure rates of hemin dissociation from native metmyoglobin, four myoglobin mutants (Ala64(E7), Ala68(E11), Phe68(E11), and Glu45(CD3)), native methemoglobin, valence hybrid hemoglobins, and two mutant hemoglobins ((alpha(Gly-E7)beta(native))2, and (alpha(native)beta(Gly-E7))2). Two kinetic phases were observed for hemin dissociation from native human hemoglobin at pH 7.0 and 37 degrees C. Valence and mutant hybrid hemoglobins were used to assign the faster phase (k = 7.8 +/- 2.0 h-1) to hemin dissociation from ferric beta subunits and the slower (k = 0.6 +/- 0.15 h-1) to dissociation from alpha subunits. The corresponding rate for wild-type metmyoglobin is 0.007 +/- 0.004 h-1.

PubMed: 8307983

実験手法

X-RAY DIFFRACTION (1.9 Å)