Characteristics and Application of a Novel Cold-Adapted and Salt-Tolerant Protease EK4-1 Produced by an Arctic Bacterium K4-1.

K4-1 from the Arctic secretes a novel cold-adapted and salt-tolerant protease EK4-1. It has the highest sequence similarity with Stearolysin, an M4 family protease from , with only 45% sequence identity, and is a novel M4 family protease. Ek4-1 has a low optimal catalytic temperature (40 °C) and is stable at low temperatures.

Novel Antioxidant Peptides Identified from Hydrolysates Prepared by a Marine Bacterium sp. JS4-1 Extracellular Protease.

Crude enzymes produced by a marine bacterium sp. JS4-1 were used to hydrolyze phycobiliprotein. Enzymatic productions showed good performance on DPPH radical and hydroxyl radical scavenging activities (45.

A Method for Detecting Antioxidant Activity of Antioxidants by Utilizing Oxidative Damage of Pigment Protein.

A simple and effective method for detecting the antioxidant activity by utilizing oxidative damage of pigment proteins was developed. In this method, phycocyanin and bovine hemoglobin pigment proteins were used as substrates attacked by free radicals; AAPH was used as a free radical initiator; and Trolox as a positive control; and the fermentation products of Lactobacillus plantarum 793, phycocyanin hydrolysates, salmon skin collagen hydrolysates, and synthetic peptides PMRGGYHY and FCVLRP are antioxidants inspected in this study. Because of being attacked by free radicals, the absorbance of the pigment proteins at their characteristic absorption peak changes with time.

Simultaneous preparation of antioxidant peptides and lipids from microalgae by pretreatment with bacterial proteases.

Chlorella can produce large amounts of lipids and therefore has great potential for biodiesel production. In this study, Chlorella protothecoides was hydrolyzed by several kinds of extracellular bacterial proteases produced by Pseudoalteromonas sp. ZB23-2, B27-3 and JS4-1 before lipid extraction.