scholarly journals Identification of three stage-specific proteinases of Plasmodium falciparum.

1987 ◽  
Vol 166 (3) ◽  
pp. 816-821 ◽  
Author(s):  
P J Rosenthal ◽  
K Kim ◽  
J H McKerrow ◽  
J H Leech
Keyword(s):  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Specific Activity ◽  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Serine Proteinase ◽  
Cysteine Proteinases ◽  
Malaria Parasites ◽  
Neutral Ph ◽  
Cysteine Proteinase Inhibitors

We have identified and characterized three stage-specific proteinases of Plasmodium falciparum that are active at neutral pH. We analyzed ring-, trophozoite-, schizont-, and merozoite-stage parasites by gelatin substrate PAGE and characterized the identified proteinases with class-specific proteinase inhibitors. No proteinase activity was detected with rings. Trophozoites had a 28 kD proteinase that was inhibited by inhibitors of cysteine proteinases. Mature schizonts had a 35-40 kD proteinase that also was inhibited by cysteine proteinase inhibitors. Merozoite fractions had a 75 kD proteinase that was inhibited by serine proteinase inhibitors. The stage-specific activity of these proteinases and the correlation between the effects of proteinase inhibitors on the isolated enzymes with the effects of the inhibitors on whole parasites suggest potential critical functions for these proteinases in the life cycle of malaria parasites.

scholarly journals Cystatins — Inhibitors of Cysteine Proteinases

1992 ◽  
Vol 3 (4) ◽  
pp. 307-332 ◽  
Author(s):  
Libuse A. Bobek ◽  
Michael J. Levine
Keyword(s):  
Common Ancestor ◽  
Molecular Level ◽  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Diverse Group ◽  
Cysteine Proteinases ◽  
Future Directions ◽  
Cysteine Proteinase Inhibitors ◽  
Physicochemical And Functional Properties

The cystatin superfamily of proteins, derived from a common ancestor, is comprised of a diverse group of potent cysteine proteinase inhibitors and antibacterial/viral agents grouped into several families. This review concentrates on family 2 cystatins, namely, the human salivary cystatins and cystatin C. Emphasis is given to their physicochemical and functional properties at both the protein and the molecular level. The role of cystatins in disease processes, including those in the oral cavity, is also discussed. Finally, future directions for cystatin research in oral biology are presented.

Involvement of cysteine proteinases in excystment of Paragonimus ohirai metacercariae induced by sodium cholate and A23187

2003 ◽  
Vol 77 (1) ◽  
pp. 21-26 ◽  
Author(s):  
T. Ikeda
Keyword(s):  
Proteinase Inhibitor ◽  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Serine Proteinase ◽  
Sodium Cholate ◽  
Cysteine Proteinase Inhibitor ◽  
Cysteine Proteinases ◽  
Serine Proteinase Inhibitor ◽  
Similar Activity

AbstractThe involvement of intrinsic proteinases in the excystment of Paragonimus ohirai metacercariae was studied in in vitro excystment induced by sodium (Na) cholate, a bile salt and A23187, a Ca2+ ionophore. The effects of various proteinase inhibitors on the in vitro excystment were examined and similar inhibitory profiles were obtained. Benzyloxycarbonyl-L-leucyl-L-leucinal (Z-Leu-Leu-H), a cysteine proteinase inhibitor and 4-(2-aminoethyl)-benzenesulfonyl fluoride (Pefabloc SC), a serine proteinase inhibitor completely inhibited excystment, while L-3-carboxy-2,3-trans-epoxypropionyl-leucylamido (4-guanidino)-butane (E-64), a cysteine proteinase inhibitor and leupeptin, a cysteine/serine proteinase inhibitor permitted partial excystment at a lower rate, but inhibited it from proceeding from the partial excystment stage. In secretions released from metacercariae during excystment, proteinase activities detected towards various fluorogenic peptidyl substrates were almost completely inhibited by Z-Leu-Leu-H and E-64, but not by Pefabloc SC. Sodium cholate induced a higher secretion of cysteine proteinases and a higher rate of excystment than A23187. Profiles of cysteine proteinase activities towards five peptidyl substrates detected were markedly different among the two secretions and the lysate of newly excysted juveniles. Newly excysted juveniles released cysteine proteinases with similar activity profiles and levels to metacercariae induced by Na cholate-incubation, whereas the release of cysteine proteinases was reduced compared with metacercariae induced by A23187-incubation. These results provide valuable information about the involvement of intrinsic proteinases in metacercarial excystment.

Antimalarial effects of vinyl sulfone cysteine proteinase inhibitors.

1996 ◽  
Vol 40 (7) ◽  
pp. 1600-1603 ◽  
Author(s):  
P J Rosenthal ◽  
J E Olson ◽  
G K Lee ◽  
J T Palmer ◽  
J L Klaus ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Metabolic Activity ◽  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Vinyl Sulfone ◽  
Antimalarial Agents ◽  
Cysteine Proteinase Inhibitors ◽  
Hemoglobin Degradation

We evaluated the antimalarial effects of vinyl sulfone cysteine proteinase inhibitors. A number of vinyl sulfones strongly inhibited falcipain, a Plasmodium falciparum cysteine proteinase that is a critical hemoglobinase. In studies of cultured parasites, nanomolar concentrations of three vinyl sulfones inhibited parasite hemoglobin degradation, metabolic activity, and development. The antimalarial effects correlated with the inhibition of falcipain. Our results suggest that vinyl sulfones or related cysteine proteinase inhibitors may have promise as antimalarial agents.

Effect of Cysteine Proteinase Inhibitors on Murine B16 Melanoma Cell Invasion in vitro

2002 ◽  
Vol 383 (5) ◽  
pp. 839-842 ◽  
Author(s):  
Natasa Sever ◽  
Metka Filipic ◽  
Joze Brzin ◽  
Tamara T. Lah
Keyword(s):  
Cell Invasion ◽  
Cathepsin B ◽  
Proteinase Inhibitor ◽  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Cathepsin L ◽  
Cysteine Proteinase Inhibitor ◽  
Cysteine Proteinases ◽  
Cysteine Proteinase Inhibitors

Abstract Various types of proteinases are implicated in the malignant progression of human and animal tumors. Proteinase inhibitors may therefore be useful as therapeutic agents in antiinvasive and antimetastatic treatment. The aims of this study were (1) to estimate the relative importance of proteinases in B16 cell invasion in vitro using synthetic, classspecific proteinase inhibitors and (2) to assess the inhibitory effect of some naturally occurring cysteine proteinase inhibitors. Serine proteinase inhibitor reduced invasiveness by up to 24%, whereas inhibition of aspartic proteinases reduced invasion by 11%. Synthetic inhibitors of cysteine proteinases markedly impaired invasion: cathepsin B inhibitors, particularly Ca 074Me, inhibited invasion from 20 40%, whereas cathepsin L inhibitor Clik 148 reduced invasion by 11%. The potato cysteine proteinase inhibitor PCPI 8.7 inhibited invasion by 21%, whereas another potato inhibitor, PCPI 6.6, and the mushroom cysteine proteinase inhibitor clitocypin had no effects. As the inhibitors that inhibited cathepsin B were in general more efficient at impairing the invasiveness, we conclude that of the two cysteine proteinases, cathepsin B plays a more important role than cathepsin L in murine melanoma cell invasion.

Novel Cysteine Proteinase Inhibitors Homologous to the Proregions of Cysteine Proteinases

2002 ◽  
Vol 3 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Y. Yamamoto ◽  
M. Kurata ◽  
S. Watabe ◽  
R. Murakami ◽  
S. Takahashi
Keyword(s):  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Cysteine Proteinases ◽  
Cysteine Proteinase Inhibitors
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