Application of chitin- and chitosan-based materials for enzyme immobilizations: a review

Bacterial synthesized cellulose — artificial blood vessels for microsurgery

Soy proteins: A review on composition, aggregation and emulsification

Biofabrication with chitosan.

Some characteristics and applications of a transglutaminase, derived from a variant of Streptoverticillium mobaraense, namely microbial transglutaminase (MTGase), are considered MTGase, mass-produced at low cost by fermentation, catalyses the crosslinking of most food proteins through the formation of an e-(γ-glutamyl)lysine bond, in the same way as well-known mammalian enzymes However, MTGase is remarkable because it is calcium independent and its molecular weight is smaller than that of other known enzymes The results of many studies suggest that MTGase, as well as other transglutaminases, has many potential applications in food processing and in other areas

Transglutaminase and its use for food processing

A microorganism producing transglutaminase was screened as an indication of hydroxamate- forming activity. The microbial transglutaminase was purified from the culture filtrate of the strain, S- 8112, which was supposed to belong to the genus Streptoverticillium. The molecular weight of the purified enzyme was found to be about 40,000 on SDS-polyacrylamide gel electrophoresis, the isoelectric point 8.9 and the optimal pH of the reaction 6~7. The present enzyme requires no calcium ions for its activity. Thus, it clearly differs from known transglutaminases derived from mammalian organs, which have been defined as calcium-dependent enzymes.

Purification and Characteristics of a Novel Transglutaminase Derived from Microorganisms

αs1-Casein and soybean globulins were polymerized and gelatinized by Ca2+-independent transglutaminase that was isolated from the culture filtrate of a microorganism thought to belong to Streptoverticillium sp. of actinomycetes. This enzyme polymerized such albumins as bovine serum albumin, human serum albumin and conalbumin in the presence of dithiothreitol. Rabbit myosin was polymerized by the present emzyme but actin was not. An RP-HPLC analysis after enzymic digestion of the polymerized asl -casein showed existence of the £-(y-Glu)Lys bond. Thus, it was confirmed that the polymerization was formed by a catalytic reaction of the transglutaminase.

Polymerization of Several Proteins by Ca2+-Independent Transglutaminase Derived from Microorganisms

Influence of gelling reaction conditions on the strength of several protein gels prepared with microbial transglutaminase (TGase) was investigated. A method was developed to gel proteins and measure gel breaking strength in a micro well plate. Enzyme concentration range for maximum gel breaking strength varied from 10 to 40 units/g protein. Maxima gel breaking strengths were achieved at 50°C for SPI, caseinate and gelatin and 65°C for egg yolk and egg white proteins. Optimum pH resulting in strong gels was pH 9 for SPI, caseinate, and egg yolk, and pH 6 for gelatin and egg white. Adjusting pH was promoted in egg white the formation of ɛ-(γ-glutamyl)lysine crosslinks and increased its gel breaking strength.

Strength of Protein Gels Prepared with Microbial Transglutaminase as Related to Reaction Conditions

Guinea pig liver transglutaminase has been found to catalyze the formation of inter- and intramolecular e-(γ-glutamyl)lysyl crosslinks in proteins. In this paper we study the formation of polymers between different proteins by reacting them with transglutaminase. Analysis of reaction products between acetylated αs1 -casein and several proteins (αs1 -, k-casein, β-lactoglobulin, soybean 11S and 7S globulin) by sodium dodecyl sulfate polyacrylamide gel electrophoresis and high-performance liquid chromatography indicated that the different proteins were polymerized through the formation of intermolecular crosslinks. This reaction may represent a procedure to improve the properties of food proteins.

Crosslinking Between Different Food Proteins by Transglutaminase

The microbial transglutaminase (TGase)-producing strain S-8112 [Agric. Biol. Chem., 53, 2613–2617 (1989)] was identified as a variant of Streptoverticillium mobaraense. We amplified a partial gene fragment by polymerase chain reaction (PCR) using oligonucleotides synthesized from the amino acid sequence of TGase, and cloned the gene for TGase using the PCR amplified fragment as a probe. The gene encoded a precursor of TGase consisting of 406 amino acid residues, which comprised the prepro region of 75 amino acid residues and the mature region of 331 amino acid residues. We expressed the TGase gene in Streptomyces lividans under a tyrosinase promoter, and found an active and mature recombinant enzyme, indicating the processing of the gene product.

Masao Motoki

Papers

Purification and Characteristics of a Novel Transglutaminase Derived from Microorganisms

Polymerization of Several Proteins by Ca2+-Independent Transglutaminase Derived from Microorganisms

Strength of Protein Gels Prepared with Microbial Transglutaminase as Related to Reaction Conditions

Crosslinking Between Different Food Proteins by Transglutaminase

Molecular Cloning of the Gene for Microbial Transglutaminase from Streptoverticillium and Its Expression in Streptomyces lividans