Lysozyme
Lysozyme single crystal
Identifiers
EC number	3.2.1.17
CAS number	9001-63-2
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / EGO
Search PMC articles PubMed articles

Lysozyme
PDB rendering based on 132l.
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 133L, 134L, 1B5U, 1B5V, 1B5W, 1B5X, 1B5Y, 1B5Z, 1B7L, 1B7M, 1B7N, 1B7O, 1B7P, 1B7Q, 1B7R, 1B7S, 1BB3, 1BB4, 1BB5, 1C43, 1C45, 1C46, 1C7P, 1CJ6, 1CJ7, 1CJ8, 1CJ9, 1CKC, 1CKD, 1CKF, 1CKG, 1CKH, 1D6P, 1D6Q, 1DI3, 1DI4, 1DI5, 1EQ4, 1EQ5, 1EQE, 1GAY, 1GAZ, 1GB0, 1GB2, 1GB3, 1GB5, 1GB6, 1GB7, 1GB8, 1GB9, 1GBO, 1GBW, 1GBX, 1GBY, 1GBZ, 1GDW, 1GDX, 1GE0, 1GE1, 1GE2, 1GE3, 1GE4, 1GEV, 1GEZ, 1GF0, 1GF3, 1GF4, 1GF5, 1GF6, 1GF7, 1GF8, 1GF9, 1GFA, 1GFE, 1GFG, 1GFH, 1GFJ, 1GFK, 1GFR, 1GFT, 1GFU, 1GFV, 1HNL, 1I1Z, 1I20, 1I22, 1INU, 1IOC, 1IP1, 1IP2, 1IP3, 1IP4, 1IP5, 1IP6, 1IP7, 1IWT, 1IWU, 1IWV, 1IWW, 1IWX, 1IWY, 1IWZ, 1IX0, 1IY3, 1IY4, 1JKA, 1JKB, 1JKC, 1JKD, 1JSF, 1JWR, 1LAA, 1LHH, 1LHI, 1LHJ, 1LHK, 1LHL, 1LHM, 1LMT, 1LOZ, 1LYY, 1LZ1, 1LZ4, 1LZ5, 1LZ6, 1LZR, 1LZS, 1OP9, 1OUA, 1OUB, 1OUC, 1OUD, 1OUE, 1OUF, 1OUG, 1OUH, 1OUI, 1OUJ, 1QSW, 1RE2, 1REM, 1REX, 1REY, 1REZ, 1TAY, 1TBY, 1TCY, 1TDY, 1UBZ, 1W08, 1WQM, 1WQN, 1WQO, 1WQP, 1WQQ, 1WQR, 1YAM, 1YAN, 1YAO, 1YAP, 1YAQ, 207L, 208L, 2BQA, 2BQB, 2BQC, 2BQD, 2BQE, 2BQF, 2BQG, 2BQH, 2BQI, 2BQJ, 2BQK, 2BQL, 2BQM, 2BQN, 2BQO, 2HEA, 2HEB, 2HEC, 2HED, 2HEE, 2HEF, 2LHM, 2MEA, 2MEB, 2MEC, 2MED, 2MEE, 2MEF, 2MEG, 2MEH, 2MEI, 2NWD, 2ZIJ, 2ZIK, 2ZIL, 2ZWB, 3EBA, 3FE0, 3LHM, 3LN2
Identifiers
Symbols	LYZ; LZM
External IDs	OMIM: 153450 MGI: 96897 HomoloGene: 121490 GeneCards: LYZ Gene
EC number	3.2.1.17
Gene Ontology Molecular function • lysozyme activity • hydrolase activity, acting on glycosyl bonds Cellular component • extracellular region • extracellular space Biological process • inflammatory response • cell wall macromolecule catabolic process • cytolysis • defense response to bacterium Sources: Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	4069	17105
Ensembl	ENSG00000090382	ENSMUSG00000069516
UniProt	P61626	Q3TXG2
RefSeq (mRNA)	NM_000239.2	NM_017372
RefSeq (protein)	NP_000230.1	NP_059068
Location (UCSC)	Chr 12: 69.74 – 69.75 Mb	Chr 10: 116.68 – 116.69 Mb
PubMed search	[1]	[2]
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Lysozymes, also known as muramidase or N-acetylmuramide glycanhydrolase, are glycoside hydrolases, enzymes (EC 3.2.1.17) that damage bacterial cell walls by catalyzing hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in a peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrins. Lysozyme is abundant in a number of secretions, such as tears, saliva, human milk, and mucus. It is also present in cytoplasmic granules of the polymorphonuclear neutrophils (PMN). Large amounts of lysozyme can be found in egg white. C-type lysozymes are closely related to alpha-lactalbumin in sequence and structure, making them part of the same family.

In humans, the lysozyme enzyme is encoded by the LYZ gene.^[1][2]

Function[link]

The enzyme functions by attacking peptidoglycans (found in the cell walls of bacteria, especially Gram-positive bacteria) and hydrolyzing the glycosidic bond that connects N-acetylmuramic acid with the fourth carbon atom of N-acetylglucosamine. It does this by binding to the peptidoglycan molecule in the binding site within the prominent cleft between its two domains. This causes the substrate molecule to adopt a strained conformation similar to that of the transition state^{[citation needed]}. According to Phillips-Mechanism, the lysozyme binds to a hexasaccharide. The lysozyme then distorts the fourth sugar in hexasaccharide (the D ring) into a half-chair conformation. In this stressed state, the glycosidic bond is easily broken.

The amino acid side-chains glutamic acid 35 (Glu35) and aspartate 52 (Asp52) have been found to be critical to the activity of this enzyme. Glu35 acts as a proton donor to the glycosidic bond, cleaving the C-O bond in the substrate, whereas Asp52 acts as a nucleophile to generate a glycosyl enzyme intermediate. The glycosyl enzyme intermediate then reacts with a water molecule, to give the product of hydrolysis and leaving the enzyme unchanged.^{[citation needed]}

Role in disease[link]

Lysozyme is part of the innate immune system. Reduced lysozyme levels have been associated with bronchopulmonary dysplasia in newborns.^[3] Children fed infant formula lacking lysozyme in their diet have three times the rate of diarrheal disease.^[4] Since lysozyme is a natural form of protection from gram-positive pathogens like Bacillus and Streptococcus,^[5] a deficiency due to infant formula feeding can lead to increased incidence of disease. Whereas the skin is a protective barrier due to its dryness and acidity, the conjunctiva (membrane covering the eye) is, instead, protected by secreted enzymes, mainly lysozyme and defensin. However, when these protective barriers fail, conjunctivitis results.

In certain cancers (especially myelomonocytic leukemia) excessive production of lysozyme by cancer cells can lead to toxic levels of lysozyme in the blood. High lysozyme blood levels can lead to kidney failure and low blood potassium, conditions that may improve or resolve with treatment of the primary malignancy.

History[link]

The antibacterial property of hen egg white, due to the lysozyme it contains, was first observed by Laschtschenko in 1909,^[6] although it was not until 1922 that the name 'lysozyme' was coined, by Alexander Fleming (1881–1955), the discoverer of penicillin.^[7] Fleming first observed the antibacterial action of lysozyme when he treated bacterial cultures with nasal mucus from a patient suffering from a head cold.^[7]

The three-dimensional structure of hen egg white lysozyme was described by David Chilton Phillips (1924–1999) in 1965, when he obtained the first 2-Ångström (200 pm) resolution model via X-ray crystallography.^[8][9] The structure was publicly presented at a Royal Institution lecture in 1965.^[10] Lysozyme was the second protein structure and the first enzyme structure to be solved via X-ray diffraction methods, and the first enzyme to be fully sequenced that contains all twenty common amino acids.^[11] As a result of Phillips' elucidation of the structure of lysozyme, it was also the first enzyme to have a detailed, specific mechanism suggested for its method of catalytic action.^[12] This work led Phillips to provide an explanation for how enzymes speed up a chemical reaction in terms of its physical structures. The original mechanism proposed by Phillips was more recently revised.^[13]

Howard Florey (1898–1968) and Ernst B. Chain (1906–1979) also investigated lysozymes. Although they never made much progress in this field, they, along with Fleming, developed penicillin.

See also[link]

• Egg allergy

References[link]

External links[link]

• Muramidase at the US National Library of Medicine Medical Subject Headings (MeSH)
• "Lysozyme: enzyme, sequence, crystallization, structure". lysozyme.co.uk. http://lysozyme.co.uk/. Retrieved 2009-01-04. 
• Proteopedia.org HEW Lysozyme

v t e PDB gallery 133l: ROLE OF ARG 115 IN THE CATALYTIC ACTION OF HUMAN LYSOZYME. X-RAY STRUCTURE OF HIS 115 AND GLU 115 MUTANTS   134l: ROLE OF ARG 115 IN THE CATALYTIC ACTION OF HUMAN LYSOZYME. X-RAY STRUCTURE OF HIS 115 AND GLU 115 MUTANTS   1b5u: CONTRIBUTION OF HYDROGEN BONDS TO THE CONFORMATIONAL STABILITY OF HUMAN LYSOZYME: CALORIMETRY AND X-RAY ANALYSIS OF SIX SER->ALA MUTANT   1b5v: CONTRIBUTION OF HYDROGEN BONDS TO THE CONFORMATIONAL STABILITY OF HUMAN LYSOZYME: CALORIMETRY AND X-RAY ANALYSIS OF SIX SER->ALA MUTANTS   1b5w: CONTRIBUTION OF HYDROGEN BONDS TO THE CONFORMATIONAL STABILITY OF HUMAN LYSOZYME: CALORIMETRY AND X-RAY ANALYSIS OF SIX SER->ALA MUTANTS   1b5x: Contribution of hydrogen bonds to the conformational stability of human lysozyme: calorimetry and x-ray analysis of six ser->ala mutants   1b5y: CONTRIBUTION OF HYDROGEN BONDS TO THE CONFORMATIONAL STABILITY OF HUMAN LYSOZYME: CALORIMETRY AND X-RAY ANALYSIS OF SIX SER->ALA MUTANTS   1b5z: CONTRIBUTION OF HYDROGEN BONDS TO THE CONFORMATIONAL STABILITY OF HUMAN LYSOZYME: CALORIMETRY AND X-RAY ANALYSIS OF SIX SER->ALA MUTANTS   1b7l: VERIFICATION OF SPMP USING MUTANT HUMAN LYSOZYMES   1b7m: VERIFICATION OF SPMP USING MUTANT HUMAN LYSOZYMES   1b7n: VERIFICATION OF SPMP USING MUTANT HUMAN LYSOZYMES   1b7o: VERIFICATION OF SPMP USING MUTANT HUMAN LYSOZYMES   1b7p: VERIFICATION OF SPMP USING MUTANT HUMAN LYSOZYMES   1b7q: VERIFICATION OF SPMP USING MUTANT HUMAN LYSOZYMES   1b7r: VERIFICATION OF SPMP USING MUTANT HUMAN LYSOZYMES   1b7s: VERIFICATION OF SPMP USING MUTANT HUMAN LYSOZYMES   1bb3: HUMAN LYSOZYME MUTANT A96L   1bb4: HUMAN LYSOZYME DOUBLE MUTANT A96L, W109H   1bb5: HUMAN LYSOZYME MUTANT A96L COMPLEXED WITH CHITOTRIOSE   1c43: MUTANT HUMAN LYSOZYME WITH FOREIGN N-TERMINAL RESIDUES   1c45: MUTANT HUMAN LYSOZYME WITH FOREIGN N-TERMINAL RESIDUES   1c46: MUTANT HUMAN LYSOZYME WITH FOREIGN N-TERMINAL RESIDUES   1c7p: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME WITH FOUR EXTRA RESIDUES (EAEA) AT THE N-TERMINAL   1cj6: T11A MUTANT HUMAN LYSOZYME   1cj7: T11V MUTANT HUMAN LYSOZYME   1cj8: T40A MUTANT HUMAN LYSOZYME   1cj9: T40V MUTANT HUMAN LYSOZYME   1ckc: T43A MUTANT HUMAN LYSOZYME   1ckd: T43V MUTANT HUMAN LYSOZYME   1ckf: T52A MUTANT HUMAN LYSOZYME   1ckg: T52V MUTANT HUMAN LYSOZYME   1ckh: T70V MUTANT HUMAN LYSOZYME   1d6p: HUMAN LYSOZYME L63 MUTANT LABELLED WITH 2',3'-EPOXYPROPYL N,N'-DIACETYLCHITOBIOSE   1d6q: HUMAN LYSOZYME E102 MUTANT LABELLED WITH 2',3'-EPOXYPROPYL GLYCOSIDE OF N-ACETYLLACTOSAMINE   1di3: ROLE OF AMINO ACID RESIDUES AT TURNS IN THE CONFORMATIONAL STABILITY AND FOLDING OF HUMAN LYSOZYME   1di4: ROLE OF AMINO ACID RESIDUES AT TURNS IN THE CONFORMATIONAL STABILITY AND FOLDING OF HUMAN LYSOZYME   1di5: ROLE OF AMINO ACID RESIDUES AT TURNS IN THE CONFORMATIONAL STABILITY AND FOLDING OF HUMAN LYSOZYME   1eq4: CRYSTAL STRUCTURES OF SALT BRIDGE MUTANTS OF HUMAN LYSOZYME   1eq5: CRYSTAL STRUCTURES OF SALT BRIDGE MUTANTS OF HUMAN LYSOZYME   1eqe: CRYSTAL STRUCTURES OF SALT BRIDGE MUTANTS OF HUMAN LYSOZYME   1gay: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gaz: Crystal Structure of Mutant Human Lysozyme Substituted at the Surface Positions   1gb0: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gb2: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gb3: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gb5: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gb6: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gb7: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gb8: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gb9: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gbo: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gbw: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gbx: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gby: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gbz: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gdw: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS   1gdx: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS   1ge0: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS   1ge1: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS   1ge2: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS   1ge3: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS   1ge4: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS   1gev: BURIED POLAR MUTANT HUMAN LYSOZYME   1gez: BURIED POLAR MUTANT HUMAN LYSOZYME   1gf0: BURIED POLAR MUTANT HUMAN LYSOZYME   1gf3: BURIED POLAR MUTANT HUMAN LYSOZYME   1gf4: BURIED POLAR MUTANT HUMAN LYSOZYME   1gf5: BURIED POLAR MUTANT HUMAN LYSOZYME   1gf6: BURIED POLAR MUTANT HUMAN LYSOZYME   1gf7: BURIED POLAR MUTANT HUMAN LYSOZYME   1gf8: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gf9: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gfa: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gfe: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gfg: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gfh: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gfj: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gfk: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gfr: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gft: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gfu: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1gfv: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1hnl: CRYSTAL STRUCTURE OF A GLUTATHIONYLATED HUMAN LYSOZYME: A FOLDING INTERMEDIATE MIMIC IN THE FORMATION OF A DISULFIDE BOND   1i1z: MUTANT HUMAN LYSOZYME (Q86D)   1i20: MUTANT HUMAN LYSOZYME (A92D)   1i22: MUTANT HUMAN LYSOZYME (A83K/Q86D/A92D)   1inu: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT THE SURFACE POSITIONS   1ioc: CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME, EAEA-I56T   1ip1: G37A HUMAN LYSOZYME   1ip2: G48A HUMAN LYSOZYME   1ip3: G68A HUMAN LYSOZYME   1ip4: G72A HUMAN LYSOZYME   1ip5: G105A HUMAN LYSOZYME   1ip6: G127A HUMAN LYSOZYME   1ip7: G129A HUMAN LYSOZYME   1iwt: Crystal Structure Analysis of Human lysozyme at 113K.   1iwu: Crystal Structure Analysis of Human lysozyme at 127K.   1iwv: Crystal Structure Analysis of Human lysozyme at 147K.   1iww: Crystal Structure Analysis of Human lysozyme at 152K.   1iwx: Crystal Structure Analysis of Human lysozyme at 161K.   The maximum number of images (100) is exceeded !