HSpI – Kinetic Mechanisms of Enzyme Inhibition and Activation

**Fingerprints of HSpI: Dependence of the parameters on [X]**

**Fingerprints of HSpI: Specific velocity plot and replot**

Featured examples

#	Enzyme Species	EC no.	Modifier	Substrate⁽¹⁾	Name given by authors ⁽²⁾	Reference⁽³⁾
1	Acetylcholinesterase Torpedo californica	3.1.1.7	Propidium	7-acetoxy-4-methyl-coumarin	Nonlinear competitive inhibition α = 6.0, β = 1, K_X = 1.2 μM	Berman (1990)
2	Cathepsin K Homo sapiens	3.4.22.38	Compound 6	Cbz-Phe-Arg-7-amino-4-methyl- coumarylamide	Hyperbolic competitive inhibition α = 3.0, β = 1, K_X = 270 μM	Novinec (2014)
3	Coagulation factor VIIa Homo sapiens	3.4.21.21	Peptide A-183 EEWEVLCWTWETCER	N-Methylsulfonyl-D-Phe-Gly-Arg-4-nitroanilide acetate	Partial competitive inhibition α = 2.2, β = 1, K_X not calculable	Dennis (2001)
4	DNA helicase Human papillomavirus 6 E1	3.6.4.12	Bisphenylsulfonaceticacid derivative 4 ⁽⁴⁾	ATP	Hyperbolic competitive inhibition α = 70, β = 1, K_X = 190 μM	White (2005)
5	DNA helicase Human papillomavirus 6 E1	3.6.4.12	Bisphenylsulfonaceticacid derivative 6 ⁽⁴⁾	ATP	Hyperbolic competitive inhibition α = 11, β = 1, K_X = 26 μM	White (2005)
6	DNA helicase Human papillomavirus 6 E1	3.6.4.12	Bisphenylsulfonaceticacid derivative 7 ⁽⁴⁾	ATP	Hyperbolic competitive inhibition α = 10, β = 1, K_X = 35 μM	White (2005)
7	Thrombin Homo sapiens	3.4.21.5	N^α-acetyl desulfo hirudin ^45-65	Tos-Gly-Pro-Arg-p-nitroanilide	Partially competitive inhibition α = 4, β = 1, K_X = 0.11 μM	DiMaio (1990)
8	Thrombin Bos taurus	3.4.21.5	N^α-acetyl desulfo hirudin ^45-65	Tos-Gly-Pro-Arg-p-nitroanilide	Partially competitive inhibition α = 2, β = 1, K_X = 0.72 μM	DiMaio (1990)
9	NAD( P )H oxidase ⁽⁵⁾ Mycobacterium tuberculosis	1.6.3.1	NAD_ox	NAD_red	Hyperbolic competitive inhibition α = 6.2±1.7, β = 1, K_X = 0.22 mM ⁽⁶⁾	Worcel (1965)
10	Aldehyde dehydrogenase (NAD⁺) Ovis aries	1.2.1.3	Propionaldehyde	4-Nitrophenylacetate (esterase activity)	Partially competitive inhibition α = 5.3, β = 1, K_X = 1.44 μM	Blackwell (1983)
11	Ferredoxin-nitrite reductase Chlamydomonas reinhardtii ⁽⁷⁾	1.7.7.1	Nitrate	Nitrite	Partially competitive inhibition α = 12.5, β = 1, K_X = 2.7 μM	Córdoba (1986)
12	Receptor protein-tyrosine kinase Homo sapiens	2.7.10.1	RG 14467	ATP⁽⁸⁾	Hyperbolic competitive inhibition α ≈ 4, β ≈ 1, K_X ≤ 30 nM ⁽⁸⁾	Hsu (1991)
13	Leukocyte elastase Homo sapiens	3.4.21.37	Heparin (17-19 kDa)	Suc-Ala₃-p-nitroanilide	Hyperbolic competitive inhibition α = 3.5, β = 1, K_X = 6.8 nM (tight-binding)	Spencer (2006)
14	Purine nucleosidase Trypanosoma vivax	3.2.2.2	Dromedary antibody variable domain fragment (VHH 1602)	p-nitrophenyl riboside	Hyperbolic competitive inhibition α = 2.9, β = 1, K_X = 71 nM	Barlow (2009)
15	Pyruvate kinase Homo sapiens	2.7.1.40	L-Phenylalanine	Phosphoenolpyruvate	Hyperbolic specific inhibition α > 1, β ≈ 1, K_X = 19 μM	Macpherson (2019)

⁽¹⁾ Always the varied substrate. In two- or more-substrate reactions the concentration(s) of the non varied substrate(s) is/are kept constant.

⁽²⁾ Name of the mechanism given by the authors in the quoted reference. α, β and the inhibition/activation constants for the modifier (X), uniformly denoted K_X, are the values specified by the authors. In some cases, missing parameters have been calculated from graphical or tabular data provided in the papers. In two- or more-substrate reactions, K_X represents an apparent constant at given concentrations of the fixed substrates and no calculations of the intrinsic values have been attempted.

⁽³⁾ Full references at the end of the page provide also the digital object identifier (doi), if available. Clicking the authors (highlighted) opens the reference in PubMed.

⁽⁴⁾ Two experiments are reported in the paper. The values shown here refer to experiment 1.

⁽⁵⁾ AMP-activated enzyme.

⁽⁶⁾ The mechanism shown in Scheme 2 (p. 3406) lacks the closure of the thermodynamic cycle between E’S and IE’S, necessary for showing the linked functions. α was calculated as K₂‘/K₁‘, the ratio of the apparent Michaelis constant at saturating [X] and K_m in the absence of modifier, from the data below equation 10 on p. 3404.

⁽⁷⁾ Wild type, strain 6145c.

⁽⁸⁾ At fixed second substrate (K1), a peptide containing the major autophosphorylation site (Tyr-1173) of the epidermal growth factor receptor. Tight-binding (quasi irreversible) slow-onset inhibition; K_X estimated by the authors. Approximate values of α and β were estimated from the data in Fig. 10.

References

Barlow JN, Conrath K, Steyaert J (2009) Substrate-dependent modulation of enzyme activity by allosteric effector antibodies. Biochimica et Biophysica Acta – Proteins and Proteomics 1794: 1259-1268. doi:10.1016/j.bbapap.2009.03.019
Berman HA, Leonard K (1990) Ligand exclusion on acetylcholinesterase. Biochemistry 29: 10640-10649. doi:10.1021/bi00499a010
Blackwell LF, Bennett AF, Buckley PD (1983) Relationship between the mechanisms of the esterase and dehydrogenase activities of the cytoplasmic aldehyde dehydrogenase from sheep liver. An alternative view. Biochemistry 22: 3784-3791. doi:10.1021/bi00285a011
Córdoba F, Cárdenas J, Fernández E (1986) Kinetic characterization of nitrite uptake and reduction by Chlamydomonas reinhardtii. Plant Physiol 82: 904-908. doi:10.1104/pp.82.4.904
Dennis MS, Roberge M, Quan C, Lazarus RA (2001) Selection and characterization of a new class of peptide exosite inhibitors of coagulation factor VIIa. Biochemistry 40: 9513-9521. doi:10.1021/bi010591l
DiMaio J, Gibbs B, Munn D, Lefebvre J, Ni F, Konishi Y (1990) Bifunctional thrombin inhibitors based on the sequence of hirudin45-65. J Biol Chem 265: 21698-21703. doi:10.1007/978-94-011-3034-9_321
Hsu CY, Persons PE, Spada AP, Bednar RA, Levitzki A, Zilberstein A (1991) Kinetic analysis of the inhibition of the epidermal growth factor receptor tyrosine kinase by lavendustin-A and its analogue. J Biol Chem 266: 21105-21112.
Macpherson JA, Theisen A, Masino L, Fets L, Driscoll PC, Encheva V, Snijders AP, Martin SR, Kleinjung J, Barran PE, Fraternali F, Anastasiou D (2019) Functional cross-talk between allosteric effects of activating and inhibiting ligands underlies PKM2 regulation. eLife 8: e45068. doi:10.7554/eLife.45068
Novinec M, Lenarčič B, Baici A (2014) Probing the activity modification space of the cysteine peptidase cathepsin K with novel allosteric modifiers. PLoS One 9: e106642. doi:10.1371/journal.pone.0106642
Spencer JL, Stone PJ, Nugent MA (2006) New insights into the inhibition of human neutrophil elastase by heparin. Biochemistry 45: 9104-9120. doi:10.1021/bi060338r
White PW, Faucher AM, Massariol MJ, Welchner E, Rancourt J, Cartier M, Archambault J (2005) Biphenylsulfonacetic acid inhibitors of the human papillomavirus type 6 E1 helicase inhibit ATP hydrolysis by an allosteric mechanism involving tyrosine 486. Antimicrobial agents and chemotherapy 49: 4834-4842. doi:10.1128/AAC.49.12.4834-4842.2005
Worcel A, Goldman DS, Cleland WW (1965) An allosteric reduced nicotinamide adenine dinucleotide oxidase from Mycobacterium tuberculosis. J Biol Chem 240: 3399-3407.