Novel inhibitors of human leukocyte elastase and cathepsin G. Sequence variants of squash seed protease inhibitor with altered protease selectivity

Journal Article · Tue Jul 11 00:00:00 EDT 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00440a002· OSTI ID:5030607

McWherter, C A; Walkenhorst, W F; Glover, G I ^[1]; Campbell, E J ^[2]

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1. Monsanto Company, St. Louis, MO (USA)
2. Jewish Hospital at Washington Univ. School of Medicine, ST. Louis, MO (USA)

Novel peptide inhibitors of human leukocyte elastase (HLE) and cathepsin G (CG) were prepared by solid-phase peptide synthesis of P1 amino acid sequence variants of Curcurbita maxima trypsin inhibitor III (CMTI-III), a 29-residue peptide found in squash seed. A systematic study of P1 variants indicated that P1, Arg, Lys, Leu, Ala, Phe, and Met inhibit trypsin; P1, Val, Ile, Gly, Leu, Ala, Phe, and Met inhibit HLE; P1 Leu, Ala, Phe, and Met inhibit CG and chymotrypsin. Variants with P1, Val, Ile, or Gly were selective inhibitors of HLE, while inhibition of trypsin required P1 amino acids with an unbranched {beta} carbon. Studies of Val-5-CMTI-III (P1 Val) inhibition of HLE demonstrated a 1:1 binding stoichiometry with a (K{sub i}){sub app} of 8.7 nM. Inhibition of HLE by Gly-5-CMTI-III indicated a significant role for reactive-site structural moieties other than the P1 side chain. Val-5-CMTI-III inhibited both HLE and human polymorphonuclear leukocyte (PMN) proteolysis of surface-bound {sup 125}I-labeled fibronectin. Val-5-CMTI-III was more effective at preventing turnover of a peptide p-nitroanilide substrate than halting dissolution of {sup 125}I-labeled fibronectin. It was about as effective as human serum {alpha}{sub 1}-proteinase inhibitor in preventing PMN degradation of the connective tissue substrate. In addition to providing interesting candidates for controlling inflammatory cell proteolytic injury, the CMTI-based inhibitors are ideal for studying molecular recognition because of their small size, their ease of preparation, and the availability of sensitive and quantitative assays for intermolecular interactions.

• OSTI ID: 5030607
• Journal Information: Biochemistry; (USA), Vol. 28:14; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BLOOD COAGULATION FACTORS
ENZYMATIC HYDROLYSIS
ENZYME INHIBITORS
AMINO ACID SEQUENCE
SERINE PROTEINASES
BIOCHEMISTRY
CATHEPSINS
INFLAMMATION
IODINE 125
LEUKOCYTES
MAN
TRYPSIN
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CHEMICAL REACTIONS
CHEMISTRY
COAGULANTS
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
HEMATOLOGIC AGENTS
HYDROLASES
HYDROLYSIS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
LYSIS
MAMMALS
MATERIALS
MOLECULAR STRUCTURE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PATHOLOGICAL CHANGES
PEPTIDE HYDROLASES
PRIMATES
PROTEINS
RADIOISOTOPES
SH-PROTEINASES
SOLVOLYSIS
SYMPTOMS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques