Chain papain

Figure 49-4. Diagram of a myosin moiecuie showing the two intertwined a-heiices (fibrous portion), the giobuiar region or head (G),the iight chains (L), and the effects of proteoiytic cieavage by trypsin and papain. The giobuiar region (myosin head) contains an actin-binding site and an L chain-binding site and aiso attaches to the remainder of the myosin moiecuie.

Fig. 19 Structure of LA-PRX (above) and degradation of LA-PRX (below), (a) Threaded a-CDs prevent hydrolysis of PLLA in LA-PRX. (b) LA-PRX converts into LA-pPRX by peptide linkage cleavage at bulky end-capping groups through action of papain, (c) Ester bond hydrolysis in the PLLA chain begins by an exposure of PLLA to water by release of a-CDs from LA-pPRX. Reprinted from [292] with permission...

Figure 20.11 Papain digestion of IgG antibodies primarily results in cleavage in the hinge region above the interchain disulfides. This produces two heavy-light chain pairs, called Fab fragments, each containing one antigen binding site. The Fc region normally can be recovered intact.

Figure 1.8. Diagrammatic representation of an antibody molecule. An antibody molecule comprises two heavy chains (dark shading) and two light chains (unshaded). These chains are held together by disulphide (-S—S-) bonds. The site of papain cleavage (yielding Fab and Fc portions of the molecule) is shown. Each antibody molecule has two potential anti-gen-binding sites.

Figure 4.5. Structure of myosin. Myosin comprises both light and heavy chains. The heavy chains may be cleaved by trypsin to generate light meromyosin (LMM) and heavy mero-myosin (HMM). Papain digestion of HMM yields subfragments SI and S2 each SI fragment contains an ATPase site and an actin-binding site. The light chains modify the activity of the ATPase.

R. Menard, J. Carriere, P. Laflamme, C. Plouffe, H. E. Khouri, T. Vernet, D. Tessier, D. Y. Thomas, A. C. Storer, Contribution of the Glutamine 19 Side Chain to Transition State Stablization in the Oxyanion Hole of Papain , Biochemistry 1991, 30, 8924-8928. 

Soybean trypsin inhibitor, papain dl, and rubredoxin have identical topologies six strands of + 1,+ 1,+ 1,. . . proceeding to the left around the barrel if the chain termini are at the bottom. However, handedness is not nearly as meaningful a property for up-and-down topologies as it is for Greek keys, since up-and-down handedness can change on addition or delection of a single strand. 

It can be assumed that the amino acids following this hinge region (Val 93 to Leu 447) are part of the head domain. The point of papain cleavage is at amino acid 82 27. TTie core part of the polypeptide chain is mainly folded in )3-sheets (34 %) and to a lesser extent (15 %) arranged in alpha-helical structures 7. In contrast with CBH I the core of CBH II possesses only 2 disulfide bridges (176-235 368-415) and four free sulfhydryl groups. Similarly to CBH I carboxyl functions are involved in the active center (Asp 175 and Glu 184) 28. 

Figure 4 SAXS-based model of CBH II (redrawn from ref. 31 with permission) Note that differently to CBH I the C-terminus of the chain is at the core domain and the N-terminus at the tail domain. The sequence of the domains from the N-terminus to the C-terminus is therefore A-B-B -C. B is a repeat of B with strong sequence homologies. The arrow indicates the papain cleavage site.

At one time, broad spectrum proteolytic enzymes (mainly papain and bromelain) were widely used to delay or minimize haze formation in beer (de Clerck, 1969). The enzymes cleaved protein chains, that when... 

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