Publisher Summary This chapter focuses on the activation and regulation of the first complement component. . The chapter outlines the history of the classical pathway of the complement system. Clq and C1 are bound and activated by immune complexes or aggregates containing IgG or IgM but not by those containing IgA, IgD, or IgE . Among IgG subclasses, IgG3 is most reactive followed by IgG1, and IgG2; intact IgG4 is minimally reactive, although its Fc region binds C1. C1-In does not efficiently regulate C1 activation induced by immune complexes. It, thus, appears that immune complex dependent activation is not under positive host regulation. This is apparently largely true. However, C1 activation by small immune complexes or complexes formed with nonavid antibody or with ratios of antigen to antibody far from equivalence, all of which are poor C1 activators, may well be regulated by C1-In.

The classical complement pathway: activation and regulation of the first complement component.

New synthetic inhibitors of C1r̄, C1 esterase, thrombin, plasmin, kallikrein and trypsin

Lipoprotein lipase and lipolysis in milk

Translocation of hormone-sensitive lipase and perilipin upon lipolytic stimulation of rat adipocytes.

https://www.jstage.jst.go.jp/article/jphs1951/35/3/35_3_203/_pdf

Pharmacological studies of FUT-175, nafamstat mesilate. I. Inhibition of protease activity in in vitro and in vivo experiments

Inhibitory effects of -guanidino acid esters on trypsin, plasmin, plasma kallikrein and thrombin.

There are at least two sites on the lipase which are concerned with catalysis: the catalytic site and the hydrophobic recognition site (lipid-binding site). The recognition site may be destroyed by mild proteolytic digestion, but the catalytic site may not be changed by this treatment. Mild treatment with trypsin caused change in the catalytic properties of hepatic triglyceride lipase; the water-insoluble ester-hydrolyzing activity of hepatic triglyceride lipase decreased, whereas the water-soluble ester-hydrolyzing activity did not change. After proteolytic digestion, hepatic triglyceride lipase resembles esterase since it hydrolyzes the water-soluble substrate better than the water-insoluble substrate. Conversely, esterase was converted to lipase by treatment with phospholipid. Cardiolipin in a concentration-dependent fashion enhanced triolein-hydrolysis of human serum carboxylesterase and this effect was associated with a dose-dependent decrease in water-soluble tributyrin hydrolysis. Based on these results, we propose the hypothesis that lipase and esterase have similar catalytic sites and that addition of a hydrophobic recognition site to esterase causes conversion of esterase to lipase (Fig. 9).

Relationship between lipase and esterase

Mechanism of the phosphorylation of thymidine by the culture filtrate of Clostridium perfringens and rat liver extract.

Alternative methods of thymidine phosphorylation in different organisms.

https://www.jstage.jst.go.jp/article/biochemistry1922/59/5/59_5_438/_pdf

Setsuro Fujii

Papers

Inhibitory effects of -guanidino acid esters on trypsin, plasmin, plasma kallikrein and thrombin.

Relationship between lipase and esterase

Mechanism of the phosphorylation of thymidine by the culture filtrate of Clostridium perfringens and rat liver extract.

Alternative methods of thymidine phosphorylation in different organisms.

The mechanism of in vitro stimulation of lipolysis by adrenaline.