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UniProtKB/Swiss-Prot P05177: Variant p.Asp348Asn

Cytochrome P450 1A2
Gene: CYP1A2
Variant information

Variant position:  348
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  LB/B
The variants are classified into three categories: LP/P, LB/B and US.
  • LP/P: likely pathogenic or pathogenic.
  • LB/B: likely benign or benign.
  • US: uncertain significance

Residue change:  From Aspartate (D) to Asparagine (N) at position 348 (D348N, p.Asp348Asn).
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 acidic (D) to medium size and polar (N)
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:  The CYP1A2*1F allele which is quite common (40 to 50%) is due to a substitution of a base in the non-coding region of the CYP1A2 gene and has the effect of decreasing the enzyme inducibility. Individuals who are homozygous for the CYP1A2*1F allele are 'slow' caffeine metabolizers. Thus for these individual increased intake of caffeine seems to be associated with a concomitant increase in the risk of non-fatal myocardial infraction (MI).
Additional information on the polymorphism described.

Variant description:  In allele CYP1A2*3; increases N-hydroxylation activity of heterocyclic amines; reduces phenacetin O-deethylation activity.
Any additional useful information about the variant.

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

Sequence information

Variant position:  348
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  516
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.

Residue conservation: 
The multiple alignment of the region surrounding the variant against various orthologous sequences.







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 2 – 516 Cytochrome P450 1A2
Helix 337 – 350

Literature citations

Functional characterization of four allelic variants of human cytochrome P450 1A2.
Zhou H.; Josephy P.D.; Kim D.; Guengerich F.P.;
Arch. Biochem. Biophys. 422:23-30(2004)

Five novel natural allelic variants-951A->C, 1042G->A (D348N), 1156A->T (I386F), 1217G->A (C406Y) and 1291C->T (C431Y)-of the human CYP1A2 gene in a French Caucasian population.
Chevalier D.; Cauffiez C.; Allorge D.; Lo-Guidice J.-M.; Lhermitte M.; Lafitte J.-J.; Broly F.;
Hum. Mutat. 17:355-356(2001)
Cited for: VARIANTS ASN-348; PHE-386; TYR-406 AND TRP-431;

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.