Identification of residues in the insulin molecule important for binding to insulin-degrading enzyme

Journal Article · Tue Aug 21 04:00:00 EDT 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00485a022· OSTI ID:6058579

Affholter, J A; Roth, R A ^[1]; Cascieri, M A; Bayne, M L ^[2]; Brange, J ^[3]; Casaretto, M ^[4]

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1. Stanford Univ. School of Medicine, CA (USA)
2. Merck Sharp and Dohme Research Labs., Rahway, NJ (USA)
3. Novo Research Institute, Bagsvaerd (Denmark)
4. Deutsches Wollforschungsinstitut an der Technischen, Aachen (West Germany)

Insulin-degrading enzyme (IDE) hydrolyzes insulin at a limited number of sites. Although the positions of these cleavages are known, the residues of insulin important in its binding to IDE have not been defined. To this end, the authors have studied the binding of a variety of insulin analogues to the protease in a solid-phase binding assay using immunoimmobilized IDE. Since IDE binds insulin with 600-fold greater affinity than it does insulin-like growth factor, the first set of analogues studied were hybrid molecules of insulin and IGF I. Removal of the eight amino acid D-chain region of IGF I (which has been predicted to interfere with binding to the 23-25 region) results in a 25-fold increase in affinity for IDE, confirming the importance of residues 23-25 in the high-affinity recognition of IDE. A similar role for the corresponding (B24-26) residues of insulin is supported by the use of site-directed mutant and semisynthetic insulin analogues. Insulin mutants (B25-Asp)insulin and (B25-His)insulin display 16- and 20-fold decreases in IDE affinity versus wild-type insulin. Similar decreases in affinity are observed with the C-terminal truncation mutants (B1-24-His{sup 25}-NH{sub 2})insulin and (B1-24-Leu{sup 25}-NH{sub 2})insulin, but not (B1-24-Trp{sup 25}-NH{sub 2})insulin and (B1-24-Tyr{sup 25}-NH{sub 2})insulin. The truncated analogue with the lowest affinity for IDE ((B1-24-His{sup 25}-NH{sub 2})insulin) has one of the highest affinities for the insulin receptor. Therefore, they have identified a region of the insulin molecule responsible for its high-affinity interaction with IDE. Although the same region has been implicated in the binding of insulin to its receptor, the data suggest that the structural determinants required for binding to receptor and IDE differ.

• OSTI ID: 6058579
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:33; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
AZOLES
BETA DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
DOSE-RESPONSE RELATIONSHIPS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMATIC HYDROLYSIS
ENZYMES
GROWTH FACTORS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HISTIDINE
HORMONES
HYDROLASES
HYDROLYSIS
IMIDAZOLES
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LEUCINE
LYSIS
MEMBRANE PROTEINS
MITOGENS
MOLECULAR STRUCTURE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDE HORMONES
PEPTIDE HYDROLASES
POLYMERIZATION
PROTEINS
RADIOISOTOPES
RECEPTORS
SOLVOLYSIS