Novel functions of human alpha(1)-protease inhibitor after S-nitrosylation: inhibition of cysteine protease and antibacterial activity.
alpha(1)-Protease inhibitor (alpha(1)PI), the most abundant serine protease inhibitor found in human plasma (at 30-60 microM), is a glycoprotein (53 kDa) having a single cysteine residue at position 232 (Cys(232)). We have found that Cys(232) of human alpha(1)PI was readily S-nitrosylated by nitric oxide (NO) without affecting inhibitory activity to trypsin or elastase. S-nitrosylated alpha(1)PI (S-NO-alpha(1)PI) not only retained inhibitory activity against these serine proteases, but also gained thiol protease inhibitory activity against a Streptococcus pyogenes protease; the parental alpha(1)PI did not have this activity. Furthermore, S-NO-alpha(1)PI exhibited bacteriostatic activity against Salmonella typhimurium at concentrations of 0.1-10 microM, which were 20- to 3000-fold stronger than those of the other NO-generating compounds or S-nitroso compounds such as S-nitrosoalbumin and S-nitrosoglutathione. NO appears to be transferred into the bacterial cells from S-NO-alpha(1)PI via transnitrosylation, as evidenced by electron spin resonance spectroscopy with an NO spin trap. Thus, we conclude that S-NO-alpha(1)PI may be generated from the reaction between alpha(1)PI and NO under inflammatory conditions, in which production of both is known to increase. As a result, new functions, i.e., antibacterial and thiol protease inhibitory activities of alpha(1)PI, were generated.
Miyamoto
Y
Y
Department of Microbiology, Kumamoto University School of Medicine, Kumamoto, 860-0811, Japan.
Akaike
T
T
Alam
M S
MS
Inoue
K
K
Hamamoto
T
T
Ikebe
N
N
Yoshitake
J
J
Okamoto
T
T
Maeda
H
H
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002401:Cathepsin B / Q000037:antagonists & inhibitors; D002417:Cattle; D003545:Cysteine; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008826:Microbial Sensitivity Tests; D009569:Nitric Oxide / Q000494:pharmacology*; D009603:Nitroso Compounds; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors; D010206:Papain / Q000037:antagonists & inhibitors; D012486:Salmonella typhimurium / Q000187:drug effects; D013917:Thrombin / Q000037:antagonists & inhibitors; D014357:Trypsin / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000494:pharmacology; D000515:alpha 1-Antitrypsin / Q000737:chemistry / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D015853:Cysteine Proteinase Inhibitors; D009603:Nitroso Compounds; D014361:Trypsin Inhibitors; D000515:alpha 1-Antitrypsin; D009569:Nitric Oxide; D010196:Pancreatic Elastase; D014357:Trypsin; D013917:Thrombin; D002401:Cathepsin B; D010206:Papain; D003545:Cysteine