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UniProtKB/Swiss-Prot P33261: Variant p.Met74Thr

Cytochrome P450 2C19
Gene: CYP2C19
Chromosomal location: 10q24.1-q24.3
Variant information

Variant position:  74
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Polymorphism
The variants are classified into three categories: Disease, Polymorphism and Unclassified.
  • Disease: Variants implicated in disease according to literature reports.
  • Polymorphism: Variants not reported to be implicated in disease.
  • Unclassified: Variants with uncertain implication in disease according to literature reports. Evidence against or in favor of a pathogenic role is limited and/or conflicting.

Residue change:  From Methionine (M) to Threonine (T) at position 74 (M74T, p.Met74Thr).
Indicates the amino acid change of the variant. The one-letter and three-letter codes for amino acids used in UniProtKB/Swiss-Prot are those adopted by the commission on Biochemical Nomenclature of the IUPAC-IUB.

Physico-chemical properties:  Change from medium size and hydrophobic (M) to medium size and polar (T)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  -1
The score within a Blosum matrix for the corresponding wild-type to variant amino acid change. The log-odds score measures the logarithm for the ratio of the likelihood of two amino acids appearing by chance. The Blosum62 substitution matrix is used. This substitution matrix contains scores for all possible exchanges of one amino acid with another:
  • Lowest score: -4 (low probability of substitution).
  • Highest score: 11 (high probability of substitution).
More information can be found on the following page

Polymorphism:  Genetic variation in CYP2C19 is responsible for poor drug metabolism [MIM:609535]. Individuals can be characterized as either extensive metabolizers (EM) or poor metabolizers (PM). The PM phenotype is inherited in an autosomal recessive manner, with the EM phenotype comprising both homozygous dominant and heterozygote genotypes. There are marked interracial differences in the frequency of this polymorphism. Poor metabolizers represent 2-5% of Caucasians, 13-23% of Asian populations, and as many as 38-79% of individuals of some of the islands of Polynesia and Micronesia. Different alleles of CYP2C19 are known: CYP2C19*1A CYP2C19*1B, CYP2C19*1C, CYP2C19*2A (CYP2C19m1 or CYP2C19m1A), CYP2C19*2B (CYP2C19m1B), CYP2C19*2C (CYP2C19*21), CYP2C19*3A (CYP2C19m2), CYP2C19*3B (CYP2C19*20), CYP2C19*4 (CYP2C19m3), CYP2C19*5A (CYP2C19m4), CYP2C19*5B, CYP2C19*6, CYP2C19*7, CYP2C19*8, CYP2C19*9, CYP2C19*10, CYP2C19*11 CYP2C19*12, CYP2C19*13, CYP2C19*14 CYP2C19*15, CYP2C19*16, CYP2C19*18, CYP2C19*19. Defective CYP2C19*2 and CYP2C19*3 alleles are characterized by a splice mutation and a stop codon, respectively, and account for most of the PM alleles. The sequence shown is that of allele CYP2C19*1B.
Additional information on the polymorphism described.

Other resources:  
Links to websites of interest for the variant.

Sequence information

Variant position:  74
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  490
The length of the canonical sequence.

The residue change on the sequence. Unless the variant is located at the beginning or at the end of the protein sequence, both residues upstream (20) and downstream (20) of the variant will be shown.

Sequence annotation in neighborhood:  
The regions or sites of interest surrounding the variant. In general the features listed are posttranslational modifications, binding sites, enzyme active sites, local secondary structure or other characteristics reported in the cited references. The "Sequence annotation in neighborhood" lines have a fixed format:
  • Type: the type of sequence feature.
  • Positions: endpoints of the sequence feature.
  • Description: contains additional information about the feature.

Chain 1 – 490 Cytochrome P450 2C19
Beta strand 72 – 77

Literature citations

Genetic variation in eleven phase I drug metabolism genes in an ethnically diverse population.
Solus J.F.; Arietta B.J.; Harris J.R.; Sexton D.P.; Steward J.Q.; McMunn C.; Ihrie P.; Mehall J.M.; Edwards T.L.; Dawson E.P.;
Pharmacogenomics 5:895-931(2004)
Cited for: VARIANTS THR-74; HIS-144; LEU-168 AND ILE-331;

Disclaimer: Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. They are not in any way intended to be used as a substitute for professional medical advice, diagnostic, treatment or care.