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UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot P14410: Variant p.Leu620Pro

Sucrase-isomaltase, intestinal
Gene: SI
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Variant information Variant position: help 620 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Type of variant: help LP/P [Disclaimer] 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: help From Leucine (L) to Proline (P) at position 620 (L620P, p.Leu620Pro). 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: help Similar physico-chemical property. Both residues are medium size and hydrophobic. The physico-chemical property of the reference and variant residues and the change implicated.
BLOSUM score: help -3 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
Variant description: help In CSID; SI accumulates predominantly in the ER. Any additional useful information about the variant.
Other resources: help Links to websites of interest for the variant.


Sequence information Variant position: help 620 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 1827 The length of the canonical sequence.
Location on the sequence: help HWLGDNTASWEQMEWSITGM L EFSLFGIPLVGADICGFVAE 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: help The multiple alignment of the region surrounding the variant against various orthologous sequences. 
Human                         HWLGDNTASWEQMEWSITGMLEFSLFGIPLVGADICGFVAE

Rat                           HWLGDNTASWEQMEWSITGMLEFGIFGMPLVGATSCGFLAD

Rabbit                        HWLGDNTATWEQMEWSITGMLEFGLFGMPLVGADICGFLAE
Sequence annotation in neighborhood: help 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.
TypePositionsDescription
Chain 2 – 1827 Sucrase-isomaltase, intestinal
Chain 2 – 1007 Isomaltase
Topological domain 33 – 1827 Lumenal
Region 110 – 1007 Isomaltase
Active site 604 – 604 For isomaltase activity
Helix 609 – 624



Literature citations
Congenital sucrase-isomaltase deficiency because of an accumulation of the mutant enzyme in the endoplasmic reticulum.
Ritz V.; Alfalah M.; Zimmer K.P.; Schmitz J.; Jacob R.; Naim H.Y.;
Gastroenterology 125:1678-1685(2003)
Cited for: VARIANTS PHE-15 AND ALA-231; VARIANT CSID PRO-620;
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.